Genetically
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 Food


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26 March 2000

Table of Contents

Genetic Engineering of Trees
Genetically Modified (GM) Foods and Crops are Unsafe
Monsanto's Cry3Bb corn
good news from the Netherlands
Robert Cohen: Truth or Consequencs
Errors, gene sequencing, patents
wot no side-effects?
Monsanto says rBGH safety is not an issue
Genetic Cranberries: UW Professor Explores the Possibilities
MEDICAL ETHICS: Principles for Human Gene Therapy Studies
"Trust me, I'm an expert" - The Royal Society's "Guidance for editors"
How to Engineer Society to Accept Science as Usual
Moral Hype
Report on the Dispersal of Maize Pollen
New terminator patent: US5723765: Control of plant gene expression
patent US5977441: Control of plant gene expression

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Date: 21 Mar 2000 02:42:51 U
From: Robert Mann robt_m@talk.co.nz

Genetic Engineering of Trees

I have felt for a few years that tree-GE is neglected relative to crop-GE and even some admittedly very threatening animal-GE. (I don't see how to make an explicit analysis of these relative dangers, which is why I use the verb 'feel'.)

It is therefore of interest that Greepneace is about to set up in my city its tree-GE HQ.

One reason for the initially surprising site choice is that already here is a main tree-GE corporation, which says it is going to list on the Nasdaq. In case youse missed this at the time, here's a glimpse of this transnational image.

Date: Saturday, 10 April 1999 16:44
Subject: [GN]Forestry Biotechnology Joint Venture

Fletcher Challenge Forests, International Paper, Monsanto Company and Westvaco Corporation Announce Forestry Biotechnology Joint Venture NEW YORK, April 6 /PRNewswire/ – Fletcher Challenge Forests (NYSE: FFS - news), International Paper (NYSE: IP - news), Monsanto Company (NYSE: MTC - news) and Westvaco Corporation (NYSE: W - news) announced today their intent to form a forestry biotechnology joint venture to produce and market tree seedlings that will improve forest health and productivity for the forestry market worldwide. The four companies will contribute $60 million (US) in total over five years to the joint venture.

The companies also announced their intent to contract with Genesis Research and Development Corporation Limited, an Auckland, New Zealand, biotechnology research company, to provide genomics research. The joint venture also will acquire forestry intellectual property from Genesis.

The CEO of Genesis R&D Corp is James D Watson (jr, as I add to discriminate against the more famous nerd), former Prof of Molecular Medicine, U of Auckland. I phoned him recently to ask how tree-GE is coming along. His answers were surprising.

  1. Nobody has made a GE-tree analogous to RR(r) soybeans etc. - they've not got past chimaeras yet. (Prof Joe will, I hope, favour us with an inimitable terse CumminsGramA on that category of compiled organism.)

  2. Nobody has yet got any intended chemical biosynthesised in such a tree.

  3. The claimed growth rates hundreds of times faster than any previous tree are bullshit. If JDjr can shave one year off the 'rotation' times of 20-30y for pines or eucalypts, he'll be gratified.

  4. Any tree that grew two order of magnitude faster than the fastest natural tree would have properties very different from the tree species it had been jigged from. For example, resistance to windthrow would presumably be weak in any such tree. (I recalled the fine eucalypt groves of Calif which many natives suppose to be also native. They were planted on the urging of Jack London after his voyage on the Snark to Australia. They grew faster than in their homeland but at loggable size turned out to have very inferior properties so most have not been turned into timber but continue to grace the Berkeley campus etc.)

  5. The "Green(r)" image of trees GEd to make less lignin so as to entail less pollution from pulp mills has made no progress toward reality.

I take this summary to be pretty plurry interesting.

The corporatized Forest Research Institute has just imported for a brief consulting tour a gene-jockey from the U of Calif. For some unknown reason he has not been in touch with me since arriving a few days ago.

Those fixated on food may need reminding that trees are not just for timber and pulp. Some exceedingly important foods come off trees. Bananas for instance - the tropics would be far less hospitable to the human if bananas suffered a pandemic. They are a favourite target for gene-jockeys claiming they will hook in vaccines. (I don't care whether the banana plant is strictly a tree - it's the vernacular meaning that largely matters in this context.) Other fruit trees are also threatened with "improvementA" by the gene-jockeys.

I heard a year ago from the WWF < jpjeanrenaud@wwfnet.org that they were organising a special effort toward control of tree-GE. I warmly welcomed this but have not heard from them since.

R

---------------------------------
Robt Mann
Mulgoon Professor emeritus of Environmental Studies, U of Auckland consultant stirrer & motorcyclist
P O Box 28878, Remuera, Auckland 1005, New Zealand (9) 524 2949


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Date: 21 Mar 2000 11:03:36 U
From: "j.e. cummins" jcummins@julian.uwo.ca

Guelph Roundtable Discussion

Genetically Modified (GM) Foods and Crops are Unsafe

21 March 2000

Prof. Joe Cummins
738 Wilkins Street, London, Ontario N6C4Z9
Telephone 519 681 5477    e-mail: jcummins@julian.uwo.ca

What are genetically modified (GM) foods and crops? GM foods and crops are products of the laboratory whose fundamental genetic make-up has been altered using genetic engineering. Genes from bacteria, viruses or animals including human have been introduced the genetic make-up of seeds of the crops that make up GM food. What is substantial equivalence? Substantial equivalence is the doctrine that maintains that if GM crops are grossly similar in composition to crops that have not been genetically modified they are equivalent to those crops and need not be labeled in the market and they need not be tested similarly to the test required for pesticides or pharmaceutical drugs. When it is found that crops are not substantially equivalent , as for example, peer reviewed and published studies showing that herbicide tolerant soy are deficient in important nutrients, the phytoestrogens, or studies showing that the Bt toxin in insect resistant corn, potato and cotton is an allergen the government does not remove the crops from the market. The government definition of substantial equivalence seems to include a caveat requiring that studies showing that GM crops are not substantially equivalent should be ignored and withheld from public scrutiny.

What is the Precautionary Principle? The precautionary principle was established internationally in the Montreal Conference on Biodiversity. It is essentially an agreement that GM crops should be proven safe for humans and the environment to be allowed to be marketed internationally. The precautionary principle supersedes the assumption of substantial equivalence. However, many Canadian bureaucrats like to pretend that the precautionary principle is just another way of saying substantial equivalence.

Is there evidence that GM crops harm people and the environment? The gene for the toxin from the bacterium Bacillus thuringiensis (Bt) is introduced into crops including corn, cotton and potato to fight insect pests. When the Bt spores are sprayed on numerous crops the spores can be washed off while the GM crops have the toxin in every cell and cannot be cleaned. Farm workers spraying Bt spores experienced allergy from the spray exposure to Bt (Bernstein et al 1999). The purified toxin (Cry) product of the Bt gene has been found to be powerfully active immunogen in mice (Vazquez-Padron et al 1999) and to stimulate mucosal antibody production (Vazquez-Padron 2000). It is very clear that the Bt toxin is a potent allergen and for that reason GM crops modified with Bt toxin are not substantially equivalent.

Round-Up ready soy has been found to be significantly deficient in the important nutrients called phytoestrogens (Lappe et al 1999). Phytoestrogens are important in preventing breast and prostate cancer. Monsanto maintains that Round-Up ready soy is substantially equivalent (Taylor et al 1999). The problem associated with Bt pollen and its impact on Monarch butterfly (Losey et al 1999) has been well discussed in the past , much of the criticism was about the fact that the experiment was done in the laboratory. Evidence from field experiments has bee ignored. quoting from Genetic Engineering News June 15,1999 Monarch Butterfly Monarch larvae feed almost exclusively on milkweed, and most of milk weed in the Midwest grow near cornfields. John Obryki PhD, professor of entomology at Iowa State university (Ames), described an experiment he and his colleagues conducted in which suggested that there may be some real danger to monarch butterfly from Bt corn.

The Iowa researchers grew a field of Bt corn and put potted milkweed plants at one and three meter distances from the edge of the field. They took the plants into the laboratory , and fed the leaves to monarch caterpillars. Controls were fed either milkweed leaves that had been washed , or leaves from milkweed plants that had pollen from non-Bt corn on them. Over 48 hours the duration of the feeding experiments , mortality reached 20% among the larvae eating Bt pollen contaminated leaves, 0% among the larvae eating washed leaves and 3% among larvae eating leaves contaminated with non-Bt pollen. Thus field experiments showed evidence of hazard to the Monarch.

Lacewing is a predator of insect pests. Hillbeck et al (1998 ) showed that the lacewing was injured by exposure to Bt corn fed prey. The German government used that evidence to suspend approval of Bt corn.

Is there a need for criminal proceedings against genetic engineers and university and government bureaucrats who injure or kill people or damage the environment? Gene therapy ( treatment of disease using altered genes) has recently faced disturbing revelations about the death of experimental subjects many of whom did not appear to have been properly appraised of the risks that they faced. Gene therapy has cost billions and used hundreds of human subjects without having produced an effective cure for any disease. Those scientists and academic administrators who fail to properly appraise experimental subjects of their risks ,then see their subjects die , face little retribution other than mild bureaucratic constraints.

Similarly, scientists and government bureaucrats who recklessly promote dangerous GM crops face little or no retribution when their experiments cause human death or severe damage to the environment. I believe that far more regard for human subjects who be shown by scientists and bureaucrats if they faced criminal charges , such as depraved indifference, when their experiments cost human life or severely damage the environment.

There are peer reviewed publications showing that GM crops are not substantially equivalent and should be withdrawn from commerce.

References


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Date: 21 Mar 2000 14:43:55 U
From: "Ericka & Rich Dana" doodles@netins.net
From: Laurel Hopwood laurel.hopwood@sierraclub.org
From Chuck Benbrook:

Monsanto's Cry3Bb corn

Highly critical comments from five environmental/ag/consumer groups were submitted March 20, 2000 to EPA on Monsanto's full registration application for Cry3Bb corn for rootworm control (another Bt-transgenic corn technology, based on Bt.tenebrionis). This technology and application are likely to trigger one of the most important and possibly contentious regulatory reviews in year 2000 in the U.S.

Anyone interested in just how much science, and what quality of science supports an application for a major new technology like Cry3Bb corn will find the comments interesting reading.

The comments were submitted on behalf of Environmental Defense, IATP, SEHN, CPI/CU, the Center for Food Safety, and Chuck Benbrook. Access the comments on Ag BioTech InfoNet at -- http://www.biotech-info.net/Cry3Bb.pdf

They print 29 pages. Please feel free to pass this announcement around to other lists.

chuck benbrook
Charles BenbrookCU FQPA site http://www.ecologic-ipm.com
Benbrook Consulting ServicesAg BioTech InfoNet http://www.biotech-info.net
5085 Upper Pack River RoadIPM site http://www.pmac.net
Sandpoint, Idaho 83864 
208-263-5236 (Voice)208-263-7342 (Fax)

For SC email list T-and-C, send: GET TERMS-AND-CONDITIONS.CURRENT to listserv@lists.sierraclub.org


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Date: 21 Mar 2000 14:45:28 U
From: wytze geno@zap.a2000.nl

good news from the Netherlands

Good news concerning GE field trials in the Netherlands: since may 1999, no new field trials have been approved. For a number of trials, the time for the Ministry of Environment to decide has expired, which means that the permission cannot be given anymore.

It could be that the Minister ( Jan Pronk) is waiting for the outcome of the European Parliament's vote on Dir. 90/220, which deals with the deliberate release of GMO's in the environment and is expected end of April. Seed and biotechindustry complain about the slowness of the Ministry, but a spokesperson for the Ministry responded that given heightened political and societal interest in the issue, the Ministry wants to be very very careful.

Last year the approval procedure of the Ministry came under fire and many questions were asked about the bias of the advisory committee, lacks in datagathering and other issues concerning field trials. The Ministry had planned to give 30-35 permissions for field trials this year, but it is unknown if this will still happen.

wytze


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Date: 21 Mar 2000 15:05:59 U
From: "Ericka & Rich Dana" doodles@netins.net
From: "David Rietz" dorietz@awod.com

Robert Cohen: Truth or Consequencs

http://www.hungerstrike.com/diary03.html#136

Tuesday, March 21

Today is the 136th day of my hunger strike.

I am sending today's diary entry to this list of people at FDA:

  1. FDA Commissioner "Jane Henney" jhenney@oc.fda.gov fax #301-443-3100
  2. FDA Senior Associate Commissioner "Linda Suydam" suydam@oc.fda.gov fax#301-443-3100
  3. CVM Director "Stephen Sundlof" ssundlof@cvm.fda.gov fax #301-594-1830
  4. CVM Deputy Director "Andrew Beaulieu" abeaulie@cvm.fda.gov fax #301-594-1830
  5. Office of the Inspector General "Kathryn Dahl" kdahl1@os.dhhs.gov #202-401-0502
  6. CVM Ombudsman "Marcia Larkins" mlarkins@cvm.fda.gov fax #594-4512
  7. Director of New Animal Drug Evaluation "Claire Lathers" clathers@cvm.fda.gov fax #301-594-2297
  8. Strategic Manager for Biotechnology, Center for Food Safety and Applied Nutrition "Jim Maryanski" jmaryans@cfsan@fda.gov fax #202-401-2893
  9. Director of the Office of Surveillance and Compliance "Linda Tollefson" tollefs@cvm.fda.gov fax #301-594-4512
  10. Director of the Office of Regulations & Policy, Center of Food Safety and Applied Nutrition, "Robert Lake" RLake@bangate.fda.gov fax #202-401-7739
  11. Congressman Dennis Kucinich http://www.house.gov/kucinich/index.htm fax #202-225-5745
  12. "Senator Barbara Boxer" senator@boxer.senate.gov fax #202-228-4056

Dear Commissioner Henney:

There comes a time in a decision-making process when the consequences of that decision should be carefully considered. Once a decision is made, it becomes too late for change.

The decision that your agency must make on April 20 will have great meaning, and the eyes of the world are firmly focused upon you.

Monsanto clearly deceived the Food & Drug Administration during the approval process for their genetically engineered bovine growth hormone (rbGH). Monsanto:

It is well accepted that a breast cancer can take up to ten years to grow from one cell into a one million-cell tumor, representing the tiniest lump a woman can feel in her breast. Recently, the New York Times revealed that there is a 50% increase ("explosion") in breast cancers in the African-American community.

When cows are injected with rbGH:

Your choices are clear, and the consequences of your actions will be unmistakable. Should you dismiss Monsanto's deception then FDA clearly erases the fine line that many still believe separates FDA and Monsanto. Such a decision will not be tolerated by the American people, and will serve to act as a symbol of Monsanto's power and FDA's inability to act as America's fiduciary.

Should FDA act to impose sanctions upon Monsanto and immediately revoke rbGH from America's marketplace, FDA will also immediately become a hero to those Americans who have criticized conflicts of interest, but who wish to confirm and celebrate America's greatness.

The choice is yours to make, but let me respectfully alert you that the consequences of your actions will be enormous.

Very truly yours,

Robert Cohen

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Date: 21 Mar 2000 15:10:09 U
From: "Gerard Owmby" rickved@bellsouth.net

Errors, gene sequencing, patents

LOS ANGELES (AP) – Scientists have found at least four significant errors in a newly issued patent of a human gene that plays a role in AIDS infection, the Los Angeles Times reported today.

The mistakes in the description of the chemical makeup of the gene raise questions about the rush to patent genes and could loosen Human Genome Sciences Inc.'s hold on the patent, genetics experts told the Times. said Christopher Broder, a former member of a National Institutes of Health team They get it wrong. They don't know the

Officials of the company, based in Rockville, Md., maintained that in spite of any mistakes in the sequence as described in the patent application, the patent issued last month will hold up to legal challenges.

The patent refers to an actual gene – not the described sequence – in a cell deposited in the American Type Culture Collection, they said. The invention we claim is the gene we deposit with the ATCC. We know that our

Still, legal experts say the sequencing errors could spell trouble for the company, which is not connected to the nonprofit Human Genome Project supported by the National Institutes of Health. If you don't make the written patent final – subject, obviously, to some arrangement for correction if there's a clerical error – then the rest of Stanford Law School professor John Barton said.

Researchers say the gene is responsible for the production of a protein that sits on the surface of a cell and is used by the AIDS virus as a docking site. Scientists targeted the gene after learning that people who have defective copies of the gene are resistant to HIV infection. Broder, now on the faculty of the Uniform Services University in Bethesda, Md., told the Times he discovered the errors in the Human Genome Sciences patent the day it was announced.

Broder said he did a quick comparison of the amino acid building blocks of the protein described in the company's patent and the protein that had been filed in a public database. He said he found that four of the 352 amino acids in the protein were incorrectly identified.


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Date: 22 Mar 2000 01:06:07 U
From: Robert Mann robt_m@talk.co.nz

wot no side-effects?

Ever since 'The Careless Technology' by Milton & Farvar (c.1972) I have taken as a rule of thumb that every technical fix will bring side-effects many of which were unforeseen and some admittedly unforeseeable.

Is this an exception?

R


USDA Scientist Who Pioneered Insect Control With Radiation Dead

WASHINGTON (AP) - Edward F. Knipling, who helped develop the radiation method of sterilizing insects harmful to plants, animals and humans, died of cancer Friday at his home in suburban Arlington, Va. He was 91.

Knipling's work was praised as an efficient, pesticide-free way in insect control and has been credited with eliminating the screwworm fly in North America and with it a threat to the livestock industry.

Knipling and colleague R.C. Bushland used radiation to sterilize male screwworm flies, which then were released to mate with female flies in the wild. The unfertilized eggs did not hatch into larvae and the screwworm population eventually was eliminated.

Before his retirement in 1973, Knipling was director of the entomology research division of the Agriculture Department's Agriculture Research Service. He won numerous awards, including the National Medal of Science in 1966.

Survivors include five children, 14 grandchildren and nine great-grandchildren.

AP-ES-03-19-00 0001EST © Copyright 2000 Associated Press.

------------------------
Robt Mann, consultant ecologist P O Box 28878 Remuera, Auckland 1005, New Zealand (9) 524 2949


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Date: 22 Mar 2000 11:16:23 U
From: "Renu Namjoshi" renu@ispchannel.com

Monsanto says rBGH safety is not an issue

Part copy [21MAR00] of the web site: http://www.monsanto.com/dairy/11_other.html

Western Europe

POSILAC has been fully evaluated in clinical trials in the United Kingdom, France, Germany and the Netherlands. These studies began in 1985 and some cows received POSILAC for up to five consecutive lactations (the United Kingdom). As in all other countries, the safety of milk from cows supplemented with BST has never been an issue and milk from the trials was marketed through normal channels.

Furthermore, in early 1993 the 12 countries of the EC unanimously agreed that POSILAC was safe and effective for dairy cows and was approved on a technical-scientific basis. However, the so-called "fourth hurdle," or the assessment of a socio-economic need for BST in a situation where there is currently an oversupply of dairy products in Western Europe, led the political bodies of the EC to declare a moratorium on the commercial sale of BST within the EC until December 1994.


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Date: 22 Mar 2000 21:58:57 U
From: "Renu Namjoshi" renu@ispchannel.com

Genetic Cranberries: UW Professor Explores the Possibilities

Marshfield News-Herald, March 21, 2000, Reference No.: 3032
http://www.biotechknowledge.com/showlib_us.php3?3032

Will cranberries get caught up in the genetic engineering battleground? That's one of questions that Brent McCown, a professor of horticulture at the University of Wisconsin-Madison, explored when, according to this story, he spoke to members of the Noon Rotary Club Monday at the Marshfield Innkeeper.

McCown was cited as saying that currently there are 200 cranberry growers in 20 Wisconsin counties and the native plant has been harvested here since the 1830s, even before statehood. There are still more than a dozen commercial beds that are more than 100 years old that are producing berries.

Cranberries are Wisconsin's No. 1 fruit crop in terms of acreage and value. The business provides 7,000 jobs and has a $350 million impact, McCown said, adding that cranberry acreage has increased 30 percent in the past five years. There is greater product competition from the United States and abroad. As a result, competition has cut the gross income per acre to about $4,000.

As a result, he added, there is a need to increase efficiency of production and to add quality to the product. New niche markets also are being sought. Today, about 10 percent of the fresh fruit is canned, frozen or made into juice drink products.

Wisconsin berries don't have the deep red color.

Genetic engineering studies could produce the color and also make the plants tolerant of environment friendly herbicides, McCown said. Early results have been positive and could address some of the product concerns. But the problem is that the commercial growers can't get the rights to put the genes that enhance the color and disease tolerance into the plants. The engineered genes are owned by a small handful of companies. There also is growing concern about the public's perception of genetically engineered products, he added.


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Date: 23 Mar 2000 18:09:41 U
From: "j.e. cummins" jcummins@julian.uwo.ca

I believe that researchers who injure people in experiments in which informed consent was not properly obtained should face criminal charges. The medical bureaucrats who authored the article below are committed to protecting their backsides and promoting injurious protocols such as the use of adenovirus vector. As evidence grows that crop GM harms people the company officials and academic bureaucrat who promote injurious protocols will cover their backsides and weep crocodile tears.

The author is director of the Program in Human Gene Therapy, University of California at San Diego School of Medicine, La Jolla, CA 92093-0634. E-mail: tfriedmann@ucsd.edu

Volume 287, Number 5461 Issue of 24 Mar 2000, pp. 2163 - 2165

MEDICAL ETHICS: Principles for Human Gene Therapy Studies

By Theodore Friedmann

Sections:
Current events sparc review
Human Experimentation Involves Risks
Informed Consent Is Crucial to Patient Protection
Dealing with Financial Conflict of Interest
Improvements Are Needed in Review and Regulation
Gene Therapy Trials Require Improved Monitoring
Conclusions
References and Notes

Current events sparc review

The human gene therapy community finds itself struggling with technical and policy problems arising from several recently publicized adverse events in human gene therapy studies. The current discussion was catalyzed by the tragic death of Jesse Gelsinger, an 18-year-old patient with ornithine transcarbamylase (OTC) deficiency who died, apparently as a direct result of the experimental gene therapy studies being carried out by investigators at the University of Pennsylvania in Philadelphia and the National Children's Medical Center in Washington, DC.

Preliminary public review of the events leading to the tragedy in the Philadelphia OTC study was presented at a recent public meeting of the Recombinant DNA Advisory Committee (RAC) of the Office of Biotechnology Activities (OBA) of the National Institutes of Health. An ongoing Food and Drug Administration (FDA) investigation has already resulted in a compulsory hold of indefinite duration being placed on gene therapy studies at the Institute for Human Gene Therapy at the University of Pennsylvania and a voluntary hold on at least one other academic institution until possible deficiencies can be corrected. One commercially sponsored study was placed on temporary hold but now has been resumed. Additional inquiries by the involved universities, the Advisory Committee to the Director of the NIH, the United States Senate, and the executive branch are under way.

These events suggest that the gene therapy community has not fully succeeded in developing mechanisms to ensure the highest possible quality of clinical research. The intention of this discussion is to derive lessons from the preliminary information available and to reexamine the principles that constitute the foundation of clinical research in gene therapy.

Human Experimentation Requires Careful Patient Selection and Protection Human disease and therapy are, eventually, best studied in human subjects. Codes of medical ethics recognize the importance of appropriate human studies, as long as they rest on strong basic and preclinical science and voluntary informed consent by patients. To be truly "informed," a patient's consent must be based on current and complete information of the procedures and their potential risks and benefits.

The patient population with potentially the most to gain in the Philadelphia OTC study, patients with the neonatal lethal form of the disease, were justifiably included in the initial study design. However, investigators were advised by their institutional review board (IRB) and medical ethics consultants that phase I experiments (in which dose and safety are being tested) would be ethically unacceptable in these infants because of the danger of implying a potential benefit to desperate parents. The next-best study population was used instead – less severely affected older patients from whom informed consent and meaningful data might be more readily obtained. There is debate in the medical ethics community whether this decision to exclude desperately ill newborns was appropriate. The quandary of patient selection in this case underscores this general dilemma in medical ethics and the unrealistic degree to which we have come to expect therapeutic results in phase I studies.

Human Experimentation Involves Risks

Human experimental studies, genetic or otherwise, are "experimental" precisely because the results are not known beforehand. Preclinical studies sometimes indicate adverse outcomes that can be readily avoided. In other instances, adverse results are found, only in retrospect, to have been foreshadowed by clues during early testing that investigators were neither alert nor wise enough to appreciate. In still other studies, adverse outcomes could not have been predicted in animals and limited human trials. Preclinical studies did not predict the discovery that the diet medication fen-phen is associated with potentially life-threatening cardiac valvular damage. Likewise, the recent withdrawal from the market by the FDA of a rotavirus vaccine came only after large-scale human experience with the vaccine.

Adverse Results Do Not Invalidate the Rationale of Gene Therapy Apparent "failures" in early phaseI/II or even phase III studies do not necessarily indicate a therapeutic wild-goose chase. Because gene therapy is highly experimental and many patients are desperately ill, serious adverse events and even deaths will occur. It is vital to understand the reasons for unexpected results or clinical failures to allow the development of corrected procedures and improved experimental methods. For example, problems with polio vaccines due to persistence of live disease-causing poliovirus in incompletely inactivated preparations and the presence of SV40 in the vaccine were identified early, corrected, and used to develop improved programs.

The development of gene therapy is similar to vaccine and drug development. Drug development is difficult and expensive, and gene therapy will not be simpler. The pharmaceutical industry, more mature and experienced than the gene therapy community, devotes enormous research and financial resources to studies of the biodistribution, pharmacological properties, stability, and metabolic properties of a potential new drug, as well as the physiological, immunological, and teratogenic effects on the host. Despite such care, because of the enormous complexity of human physiology and disease, and because even the most extensive animal data do not always faithfully predict responses in humans, adverse clinical responses have occurred and will again.

The same understanding of pharmacokinetics and mechanisms has not been available for gene therapy trials. Some clinical applications have simply outstripped scientific understanding of the disease model or the properties of the vectors, resembling an army too far ahead of its supply lines. Despite clinical urgency, there is a need to develop a similar degree of rigor for gene transfer agents as for small molecule therapeutics or viral vaccines.

Despite the caveats regarding the need for better knowledge, the search for optimum methods should not paralyze attempts to use available tools to conduct clinical research studies. To make progress, one must accept the limitations of knowledge and simultaneously use available information to ease suffering and to continue research into improvements in technology.

Informed Consent Is Crucial to Patient Protection

The single most important mechanism for ensuring patient protection from inherent risks of clinical experiments, unrealistic expectations, and potential conflicts of interest of the investigator is accurate and full disclosure of potential risks and benefits and a well-executed informed consent process. For gene therapy studies, the FDA and RAC review the adequacy of locally approved informed consent procedures during the protocol approval process. The FDA concluded that there were deficiencies in the informed consent process in the OTC study that resulted in incomplete disclosure of all potential risks to the subjects or their families. Additional troublesome public revelations of potential lapses in quality control and in patient protection have been made for other gene therapy studies.

Exaggerated expectations and potential conflicts of interest of investigators pose additional problems to the informed consent process. In 1995, an NIH advisory committee chaired by Stuart Orkin and Arno Motulsky criticized the gene therapy community for its overly optimistic public portrayal of gene therapy experiments and for unsubstantiated claims for efficacy

  1. There is still too ready a tendency by some in the gene therapy community to exaggerate potential benefits at the expense of full disclosure of potential risks. If that tendency is the result of optimism, it is at least unfortunate and should be guarded against. If it was determined that risks were intentionally omitted or misstated, appropriate sanctions by the gene therapy community and oversight bodies should be applied.

    Dealing with Financial Conflict of Interest

    The issue of conflicts of interest is magnified by the very large role that biotechnology and pharmaceutical industries have come to play in gene therapy. In many cases, academic investigators have had to forge commercial collaborations to implement clinical studies because of the high costs (production and testing of a gene vector usually exceeds several hundred thousand dollars). Although commercial interactions have facilitated clinical studies, they have also introduced corporate financial interests and investigator economic conflicts. Therefore, at minimum, involved investigators should disclose direct commercial ties in the informed consent process. Those investigators with direct financial interest in the study outcome should recuse themselves from patient selection, the informed consent process, and study direction.

    Improvements Are Needed in Review and Regulation

    During the early phase of clinical studies of human gene transfer, the RAC played a major role by providing an avenue for public evaluation of the scientific basis and patient protection aspects of a proposed study. The FDA shared responsibility for oversight of gene therapy studies through its traditional regulatory function of ensuring safety and efficacy. In 1997, in response to an advisory committee report to the NIH director, the FDA assumed the principal regulatory and oversight responsibility for gene therapy proposals, and the RAC was given the function of catalyzing public awareness and understanding of the issues of gene therapy. It also retained a secondary responsibility to determine whether studies submitted to the FDA utilized technological concepts and tools so novel that they required further public review.

    An important difference between the RAC and FDA processes is that the RAC reviews of proposals and adverse-event reporting are public and open, whereas FDA is required by statute to carry out these functions privately and without provision for public disclosure. In a field as immature and filled with public interest and concern as gene therapy, more, rather than less, public review seems desirable. A cohesive mechanism must be developed in which primary regulatory control stays with the appropriate regulatory agency – the FDA – but which more effectively takes advantage of the advisory role of the RAC or a RAC-like body and also uses the RAC as a conduit for public discussion and disclosure before protocol approval. It is encouraging that discussions are under way between the RAC, FDA, and NIH through the Advisory Committee to the NIH director on potential mechanisms to provide this kind of process.

    Gene Therapy Trials Require Improved Monitoring

    For the field to progress, investigators must have more ready access to the clinical experience in other studies, and it is therefore particularly encouraging that the OBA has reaffirmed its intention to develop a gene therapy database that will make the occurrence and nature of adverse events available online to other gene therapy investigators

  2. Such a database can only succeed if investigators report their adverse events, and disclosure is useful only if mechanisms exist to collate, evaluate, and promulgate such information.

    The existence of widely different reporting requirements has contributed to uncertainty and, quite probably, to deficiencies in reporting. The FDA requires that serious, unexpected, or related events be reported to the agency within 7 days if there is a patient death, or within 15 days for other serious adverse events. All other events are to be included in annual reports

  3. The words "serious," "unexpected," and "related" allow room for interpretation by investigators and study sponsors; the NIH requirements are less flexible. It is therefore possible, as the oversight agencies and several investigators have recently discovered, to be in compliance with the FDA requirements but not with the NIH guidelines. The NIH has recently proposed strengthening its reporting requirements through amendments of the NIH guidelines in which the definition of adverse events is clarified, and there is notification that such reports may not contain any confidential trade secrets or commercial and financial information

  4. The NIH has also notified all federally supported institutions to review their policies and procedures to ensure that they are in compliance with reporting requirements

  5. The FDA has stated that it will notify the RAC of the receipt of all adverse events in a gene therapy study (6).

Conclusions

Scientific and policy problems in gene therapy studies, together with the explosive growth of clinical studies, challenge the academic gene therapy community, commercial biotechnology and pharmaceutical firms, regulatory agencies, and professional societies such as the American Society of Human Gene Therapy to work together to improve current practices and infrastructures. Announcements of new initiatives for FDA and NIH that would require earlier review of researcher's plans for monitoring safety and quarterly meetings to promote communication are encouraging developments.

Further critical steps toward that goal would include RAC determination of the need for full public evaluation of protocols before investigational new drug (IND) assignment by FDA and IRB approval; the development of a single, uniform mechanism for reporting adverse events to the RAC, FDA, and other relevant agencies; establishment by OBA of its proposed public database of all adverse events; and nonparticipation of investigators with financial interests in study outcomes in patient selection, the informed consent process, and direct management of clinical studies. While there is need for improvements, there is also much to celebrate – major technical advances that promise imminent proof that the lives of patients can eventually be made better by gene therapy.

References and Notes

  1. S. Orkin and A. Motulsky, http://www.nih.gov/news/panelrep.html , 7 December 1995.

  2. Testimony of A. Patterson, http://www4.od.nih.gov/oba/patterson2-00.pdf , 2 February 2000.

  3. FDA Manual of Regulatory Standard Operating Procedures and Policies, http://www.fda.gov/cber/regsopp/91101.htm http://www.fda.gov/cber/regsopp/91102.htm and http://www.fda.gov/cber/ind/21cfr312.pdf

  4. Minutes of RAC meeting, 5 September 1999, http://www4.od.nih.gov/oba/9%2D99pro.htm

  5. Letter from A. Patterson to federally funded institutions, 22 November 1999.

  6. Letter from K. Zoon to Investigational New Drug Sponsors and Principal Investigators, http://www.fda.gov/cber/ltr/gt110599.htm , 5 November 1999.

The author is a member of the Recombinant DNA Advisory Committee (RAC). These comments are not intended to reflect the views of that Committee or of the National Institutes of Health.


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Date: 24 Mar 2000 10:05:46 U
From: wytze geno@zap.a2000.nl

Biotech Activists wrote:

===================================================
From List: Biotech Activists biotech_activists@iatp.org
Date Posted: 03/24/2000
Posted by: M.W.Ho@open.ac.uk
===================================================

The two reports below will appear in the next ISIS (Institute of Science In Society) News (#4). They alert scientists and journalists to an extremely worrying trend in which the scientific establishment is using its influence to effectively stifle dissent and minority views, such as those of us who are warning of the hazards of genetic engineering. If you wish to use them in anyway, please let us know (contact details at the end).

Mae-Wan Ho Director, Institute of Science in Society http://www.i-sis.org C/o Biology Department Open University Walton Hall Milton Keynes MK7 6AA, UK Tel:44-1908-653113 Fax:44-1908-654167 e-mail: m.w.ho@open.ac.uk i-sis@dircon.co.uk

"Trust me, I'm an expert" - The Royal Society's "Guidance for editors"

The Royal Society, more or less by definition the scientific establishment in the UK, has recently issued a set of recommendations entitled "Guidance for editors", which is reproduced with strong approval in the House of Lords Select Committee on Science and Technology Report on Science and Society (see How to Engineer Society to Accept Science as Usual, below). They obviously intend the document to be taken very seriously, because they begin by quoting the Press Complaints Commission Code that, "newspapers and periodicals must take care not to publish inaccurate,misleading or distorted material", and warns that "Editors must be able to demonstrate that the necessary steps have been taken". This is clearly meant as more than merely some helpful suggestions.

Everyone is in favour of accurate, genuine science reporting. We would not like to see so-called creation science treated seriously in the press, for example. There are, however, some very worrying aspects about this document. It ignores some of the basic principles of scientific enquiry and practice, not to mention the freedom of the press.

"Journalists", we are told, "must make every effort to establish the credibility of scientists and their work". Yes, but how is this to be done? The Royal Society will publish a directory that provides a list of scientists for the purpose. Before interviewing a scientist, the journalist will be expected to have consulted the officially nominated expert in the field, who will be able to say whether the scientist in question holds correct views.

Balance can be a problem for journalists: in politics it may be proper to give equal time to Government and Opposition, but things aren't so simple in science. Someone making a programme on smoking is not obliged to devote half the time to those few scientists who still insist that it is not harmful. The Royal Society, however, goes much further. "Newspapers may suppose that they have produced 'balanced' reports by quoting opposing views.." Not so, if "the opposing view is held by only a quixotic minority."

Journalists are told to identify, wherever possible, a majority view, and that is the one they should present. The majority view may turn out to be wrong, but such instances, we are told, are the exceptions rather than the rule. Perhaps they are, but the BSE crisis shows what can happen when those in authority are able to prevent a minority view being heard.

The Royal Society acknowledges that it is important for scientists to communicate via the media, but is concerned that some scientists may be seeking publicity to further their careers or to make exaggerated claims. To counter this, the media should contact "scientific advisers" (again, presumably supplied by the Royal Society) who could establish the authenticity of any story.

On the matter of "uncertainty", "journalists should be wary of regarding uncertainty about a scientific issue as an indication that all views, no matter how unorthodox, have the same legitimacy." The Royal Society insists that it is peer review that confers legitimacy on scientific claims. Up to a point, we agree, though even they admit that the process is not infallible. Hans Krebs' paper on the cycle that bears his name is not the only important one to have failed peer review.

There are other important caveats. First, many new scientific results are presented at conferences before they have been subjected to peer review. No one expects scientific journalists to wait until they are accepted for publication, which may be months later. Peer review is not and never has been a precondition for being brought to the attention of the public.

Second, where there is the possibility of danger to health or to the environment, it can be totally counter to the public interest to wait for peer review. If Dr Arpad Pusztai's work did not have possible implications for health, he would not have spoken of it before peer-review and publication, for which he was condemned by the Royal Society. Holding back on a scientific claim until everything is settled is one thing; not alerting the public soon enough to a possible danger is another. Of course, if Pusztai's data had not had potentially serious implications, it is doubtful whether the Royal Society or anyone else would have reacted as they did, which is in itself a point that should worry us.

Finally, it is not only via the press that scientific claims can directly affect the public. The scientific data submitted by commercial companies to gain regulatory approval for their products are seldom properly peer-reviewed or published, either in scientific journals or in the press. The secret memoranda of the US Food and Drug Administration which came to light as the result of the Biointegrity civil lawsuit against the agency are a case in point (Surely, journalists as well as the public can be credited with critical judgement when the science is clearly explained. Part of our social responsibility, as scientists, is to promote genuine, critical public understanding of science and to encourage open debate in terms that the public can understand. It is the role of journalists to help scientists communicate real science to the public, not merely the views of one body of scientists.


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Date: 24 Mar 2000 10:05:46 U
From: wytze geno@zap.a2000.nl

Biotech Activists wrote:

===================================================
From List: Biotech Activists biotech_activists@iatp.org
Date Posted: 03/24/2000
Posted by: M.W.Ho@open.ac.uk
===================================================

Mae-Wan Ho Director, Institute of Science in Society http://www.i-sis.org C/o Biology Department Open University Walton Hall Milton Keynes MK7 6AA, UK Tel:44-1908-653113 Fax:44-1908-654167 e-mail: m.w.ho@open.ac.uk i-sis@dircon.co.uk

How to Engineer Society to Accept Science as Usual

House of Lords Report on Science and Society

Some years ago, I listened to three popular science lectures at a seminar organized by Copus, the Committee on the Public Understanding of Science, formed in 1986 in the UK by the Royal Society, the Royal Institution and the British Association for the Advancement of Science. At the end, the lectures were judged. The one that was most praised was on a familiar topic, and while it did convey some real information, it was clear that the chief criterion was that it was the most entertaining. A second, well presented and providing an accessible introduction to an important topic, was much less highly rated. The public understanding of science had clearly come second to science as entertainment.

That incident symbolises for me the problems with the relationship between science and society, which a House of Lords Select Committee addresses in a new Report (Science and Society, Select Committee on Science and Technology 3rd Report, Session 1999-2000, House of Lords, The Stationery Office, London). This is the result of an extensive consultation exercise. Many non-government organizations including ISIS made submissions; and ISIS was cited explicitly twice.

The Report begins, appropriately enough, by noticing that there is a crisis of public confidence in science, brought on by what it referred to as the "BSE fiasco". In poll after poll, scientists, especially those working for the government and industry are among the least trusted. It also notices that instruments like Copus need more dialogue with the public, rather than just a one-way information to the public. In fact, the Report recommends extensive dialogues with the public, not just for the Government's own Office of Science and Technology (OST) and Copus, but as part of the brief of every research organization and learned institution. However, it gives no indication as to how public aspirations are to feed into science or policy decisions, or have any influence on them.

On the contrary, it explicitly states, "To prohibit science from progressing without express public support in advance would be retrograde and repressive, and would stifle creative scientific research or drive it overseas." No, that is not what the Select Committee is recommending. Instead, dialogues with the public are "intended to secure science's "licence to practice", not to restrict it". Translated into ordinary language, "dialogue" is really a public-relations exercise, in order to allow scientists to do whatever they want to do in the first place. So, astonishing as it may seem, there is no mention of science and social responsibility, nor ethics or the public good, as one would expect in a report on science and society.

In the Chapter on communicating uncertainty and risk, it commends the guidelines for scientific advice issued by the Office of Science and Technology (OST), the main theme of which is "openness". So, where scientific advice is uncertain, this should be admitted from the start. But does uncertainty have any real impact on policies? No. The precautionary principle is not mentioned even once.

Strangely enough, in the same chapter on communicating uncertainty and risk, they admit that while scientific input to policy traditionally relies on "independent experts", "the concept of independence has become problematic, particularly because of the increasing commercialisation of research". So, what is the solution for the lack of independence in science? Scientists, they say, "must robustly protect and vindicate their independence", which is more easily said than done. "Sponsorships and affiliations must be openly declared, and must not be assumed to colour the quality or outcome of the science provided that the research output is submitted to peer review and published in the academic literature".

Again, that is more pious hope than a real solution. Declaring interests does not automatically guarantee lack of conflict of interests when scientific advice is given, and scientific data submitted by commercial companies for product approval are almost never published in the academic literature. The Report has to admit the difficulties, and calls for a "radically different approach to the process of policy-making in areas involving science". What exactly does that amount to? That the Government should press for something like the OST guidelines to be adopted at EU Commission level, and that the Interdepartmental Liaison Group on Risk Assessment should look into current research on how risk information is received by the public. In other words, yet another exercise on how best to window-dress for the public.

That is not all. There is another more worrying agenda. The chapter on Science and the Media urges the Press Complaints Commission (PCC), in bold print and in the strongest terms, to adopt the Royal Society Guidelines: "We recommend these guidelines, and we urge the PCC to adopt and promulgate them. In doing so, the PCC should make it clear that they are aimed not just at specialist science correspondents, but at all journalists who find themselves dealing with science, including those on the news desk."

The Royal Society Guidelines effectively stifle dissent within the scientific community and promulgate the views of the establishment (see "Trust me, I'm an expert", above). For good measure, the House of Lords Select Committee adds several comments, the first aimed at discouraging sensational headlines such as those that might damage the image of GM crops; the second, incredible as it may seem, attempts to purge the word, "safe" from the vocabulary of the media. "The very question "Is it safe?" is itself irresponsible, since it conveys the misleading impression that absolute safety is achievable." This frontal attack on the English language is actually a veiled attempt to undermine the precautionary principle in its most important form, which can truly safeguard human health and the environment. It entails a reversal of the present onus of proof. In other words, instead of requiring civil society to prove something harmful before it can be withdrawn or banned, perpetrators have to prove something is safe before it can be approved, especially where the product is of no proven benefit to society.

The admission of uncertainty in science is an important step. The role of science is to set precaution based on uncertain evidence: the precautionary principle is part and parcel of sound science. It is time the scientific establishment put an end to the abuse and misuse of scientific evidence that has allowed corporations to endanger human health and the environment with impunity for the past fifty years.

Mae-Wan Ho Director, Institute of Science in Society m.w.ho@open.ac.uk i-sis@dircon.co.uk

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Date: 24 Mar 2000 20:03:29 U
From: "j.e. cummins" jcummins@julian.uwo.ca

You will all be happy to learn biotechnology aims to save the world :-) Plant biotechnology Moral dilemmas [Editorial overview]

Richard B Flavell

Moral Hype

Current Opinion in Plant Biology 2000, 3:143-146.

Abstract
There is no abstract for this article. The text below is the first paragraph of text within the article.

Will transgenic plants pervade global agriculture?

In the past year this has probably been the most important issue involving agricultural biotechnology. In Europe especially, many arguments have been used by those attempting to terminate deployment of the technology and, in consequence, many large retailers in the UK have announced that they will not stock products containing transgenic organisms. The arguments used against plant biotechnology by pressure groups and sold by the media have sickened the scientific community.

For two decades, scientists have believed that the creation of transgenic plants is one of the most important discoveries in the history of plant breeding, and one which is capable of helping agriculture and hence societies in countless ways. Should we be surprised by the debate or its intensity? I believe we should welcome the debate because the potential value of the technology is so substantial that its products are likely to populate the world everywhere forever more. Lack of debate would trivialize both the importance of the scientific discoveries and our interest in caring for the world.


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Date: 25 Mar 2000 10:44:33 U
From: Cliff Kinzel ckinzel@mum.edu

Report on the Dispersal of Maize Pollen

RESEARCH PAPER

Campaigning for organic food and farming and sustainable forestry

A Report on the Dispersal of Maize Pollen

JANUARY 1999

Compiled by

Dr Jean Emberlin, Beverley Adams-Groom BSc and Julie Tidmarsh BSc
National Pollen Research Unit, University College, Worcester WR2 6 AJ

commissioned by

SOIL ASSOCIATION

Based on evidence available from publications and internet sites

Sections:
1. SUMMARY
2. INTRODUCTION
3. FEATURES OF MAIZE POLLEN AND POLLINATION
4. EVIDENCE OF MAIZE POLLEN DISPERSAL FROM MONITORING SURVEYS
5. ESTIMATES OF POLLEN TRANSPORT BY THE WIND IN THE VICINITY OF THE CROP AND RATES OF CROSS POLLINATION
6. POTENTIAL LONG RANGE DISPERSAL
7. THE TRANSFER OF MAIZE POLLEN BY BEES AND OTHER INSECTS
8. DISCUSSION AND CONCLUSIONS
9. REFERENCE LIST
10 (a) SEARCHES COMPLETED
10( B) MAIZE POLLEN DISPERSAL: WEB SITES OF INTEREST

1. SUMMARY

The report reviews evidence from published sources and also from communications from named authorities about maize pollen dispersal. Background material is given on the characteristics of maize pollen including morphology and duration of viability, together with quantities produced and the salient features of pollination.

This information is used with data from empirical studies, dispersion theory models and particle deposition theory to give estimates of deposition rates and concentrations of pollen remaining airborne downwind from a source. However it is not possible to provide accurate assessments for practical use as most empirical work has been done within a narrow range of weather conditions and many studies suffer from the constraints of monitoring only close to the source and of errors in sampling. For example, evidence from previous work can be used as a basis for generalised estimates of percentages of pollen concentrations remaining airborne downwind in low to moderate wind speeds compared with concentrations at 1m from the source. These are approximately 2% at 60m, 1.1% at 200m and between 0.75 % and 0.5 % at 500m. The implications of these figures for potential cross pollination are considered but it is emphasised. that they should be used as rough guidelines only. In addition it should be noted that dispersal gradients would be altered by factors such as climatic conditions and local topography.

Transport on the airflow over longer distances is likely to occur under a range of weather situations including uplift and horizontal movement in convection cells, and uplift and transport in frontal storms. As the maize pollen grains remain viable for about 24 hours in normal weather conditions pollination could occur at sites remote from the source ( e.g. 180 km).

Dispersal away from the vicinity of the crop also takes place by carriage on bees. Evidence is cited that maize pollen is collected by bees in notable amounts. In this way the pollen is transported several miles from the crop plot in suitable weather conditions.

In any assessment of pollen flow from maize plots consideration should be given to the limitations of evidence from empirical studies and from results based on theoretical models. Acknowledgement must be given to the potential movement of maize pollen by bees and the possibilities of long range transport under certain weather conditions.

2. INTRODUCTION

This report examines the evidence for patterns of pollen dispersal from maize and considers the potential distances for effective pollination between different plants. It utilises a range of available information including empirical data from specific monitoring experiments, dispersion theory models, particle deposition theory, evidence of maize pollen transport by insects and aerobiological evidence from studies of long range transport of pollen.

The report discusses the evidence for patterns of maize pollen dispersal by wind in the vicinity of the crop and also examines the probability of longer range dispersal either by carriage on vectors or by long range transport. The probability of cross pollination events occurring between GM maize and ordinary maize is assessed for various separation distances.

3. FEATURES OF MAIZE POLLEN AND POLLINATION

Maize (Zea mays) is a highly variable, naturally cross-pollinated, markedly heterogeneous, complex species, in which all forms hybridise freely (Purseglove, 1972). It is generally pollinated by wind and gravity (anemophilous) and is also visited by bees (e.g. Percival 1950) (see section 6).

3.1 The maize pollen grain; morphology and duration of viability.

Maize pollen is amongst the largest of that of the grass (gramineae) family with dimensions in the region of 90 to 125 x 85 microns (Erdtman, 1952, Smith, 1990). The grains of pollen are usually mono-porate, more or less spheroidal to ovoid and with the aperture as a rule slightly protruding, crassimarginate and operculate (Erdtman, 1952). The grain has a volume of about 700 x 10-9 cm3 and a weight of about 247 x 10-9 g (Miller 1985; Goss 1968).

Published data for the length of time that maize pollen remains viable under natural conditions differs from about 24 hours through to several days. In artificially warm conditions or exceptionally hot weather this time could be reduced to a few hours. Conversely in cool conditions it could be extended to 9 days. Purseglove (1972) mentions maize pollen vitality as being about 24 hours, but is killed more rapidly in very hot dry weather. Jones and Newell (1948) refer to Pfundt (1910) who reported that Zea mays pollen lasts for one day and they also quote the following: The maximum retention of the fertilising power of corn pollen is reported by Knowlton (1922) to be 70 to 80 hours at a temperature of 5o to 10o C and a humidity of 50 to 80% . However, McCluer (1942) reports that when corn pollen was kept dry it retained its viability for several days. The research of Jones & Newell (1948) in 1944 and 1945, used two methods for determining the longevity of maize pollen viability. Firstly, they refrigerated the pollen in the tassel and found that the pollen would set seed with decreasing success over 9 days. Secondly, they used pollen that had been stored in a beaker in a refrigerator and that was viable, again with decreasing success, over 8 days. In both cases the first two days were very successful. Jones & Newell (1948) also found that maize pollen stored in pollinating bags in direct sunlight under a maximum temperature of 96oF was effective in fertilising silks for only 3 hours, while pollen stored in the shade of the plants under a maximum temperature of 86oF remained viable for 30 hours. They suggest that cool temperature and high relative humidity appear to be important factors in extending the life of the pollen.

3.2 Pollination.

The maize plant is monoecious and diclinous, with male and female flowers borne separately on the same plant. The male flower is called a tassel and the female flower is called the ear , while the style is usually called a silk , being long and thread-like. Maize is protandrous with pollen being shed before the silks are receptive, but as there is some overlap, up to five per cent self-pollination can occur. The tassel spreads fully before anthesis begins. Opening of the flower begins near the middle of the central spike and passes upwards and downwards, followed by the lateral branches, and ends with the tips and bases of the lower branches.

The upper flower of each pair of pair of spikelets usually opens before the lower, so that anthesis may take place in two waves. A tassel sheds pollen from 2-14 days, more usually 5-8 days, with maximum shedding about the third day (Purseglove 1972). A corn plant sheds its pollen on several successive days with dehiscence occurring in the mornings between 630 and 1100 hours, although it may be delayed by two hours in cold, cloudy weather ( Miller 1985).

The oldest spikelets are at the base of the cob and their silks begin to elongate before the upper spikelets and are the first to protrude from the husks, 2-3 days after pollen has begun to shed on the plant. Under favourable conditions, all the silks emerge during a period of 3-5 days and are receptive on emergence and can remain so for 14 days. The silks dry up on pollination, but grow abnormally long and remain turgid if not pollinated. The pollen grains are caught on the moist sticky stigmatic hairs and germinate immediately. Fertilisation of the ovule occurs 12-28 hours after pollination, during which time the pollen tube may have traversed a distance of 25 cm down the longest silks. Although there is usually an overlap of pollen shedding and silk emergence on the same plant, under normal field conditions at least 95% of the ovules are fertilised by pollen from other plants. Drought and unfavourable weather may result in silks emerging after most of the pollen has been shed (Purseglove 1972).

3.3 Pollen Quantities.

Maize pollen is produced in enormous quantities. Each of the numerous florets within a tassel contains three anthers, each of which produces in the order of 2,000 (Miller 1985 ) or 2,500 grains (Kiesselbach 1949) to 7,500 (Goss, 1968) pollen grains, depending on the plant, the variety, and the conditions of growth. This means that a spikelet produces c.15,000 grains, and a tassel between 2-5 million grains. Estimates for the numbers of pollen grains produced by an average-sized plant range from 14 million (Miller 1985), to about 50 million (Miller 1985), to fertilise approximately 1000 kernels per plant (Evans, 1975) so that there are 20,000 to 30,000 pollen grains for each silk (Purseglove, 1972). This high ratio of pollen grains per female flower available for fertilisation is typical of plants fertilised by wind pollination or anemophilous plants such as corn and pine.

Nowakowski and Morse (1982) found that iAumany sweet corn varieties produce over 150 pounds of pollen per acre . They collected sweet corn pollen from the plants using paper cones and found that even more pollen was collected by taking plants into the still conditions of a laboratory the day before pollen shedding started. Although a field of maize may release pollen over a period of up to 13 days each plant will be active for less than this. An average of 3.5 g of pollen was produced per plant in total in their experiments. Maize is typically cultivated at 20,000 plants per acre giving a pollen output of approximately 154 pounds/ 70 Kg per acre.

Table 1 : Summary of salient features of maize pollen

Grain size c.90 m (with approx. range 85- 125)

Deposition coefficient Cap . 0.20

Terminal velocity Vs 20 cm s-1

Vg ( velocity of deposition ) 40 cm s-1

Duration of viability 3 hours to 8 days depending on conditions

4. EVIDENCE OF MAIZE POLLEN DISPERSAL FROM MONITORING SURVEYS

4.1 Introduction

Numerous trials have been conducted on maize pollen dispersal because of its economic and archaeological importance. Many of these studies were done in the 1940s through to the 1970s over short downwind distances ( c.50 to 500m ) to investigate exclusion distances, or within crop stands to investigate cross pollination ( see 4.3 ). Most of the studies have examined the deposition gradients of pollen with distance from the crop and some have sampled air borne pollen at low level. There has been little consideration of vertical profiles of maize pollen concentrations or of dispersal potential other than that in the immediate vicinity of the crop in the predominant downwind direction. All of the studies suffer from the disadvantage that the work was carried out in a limited range of weather conditions. Some work has also been constrained by problems with sampling efficiencies of monitoring equipment.

The data from some of these trials has been used by various workers in dispersion models to produce generalised patterns of dispersion and to predict downwind rates of deposition and airborne concentrations of pollen. The results of this type of work are often quoted without reference to the constraints of the models and the complexity of particulate dispersion patterns. Any numerical estimates for the gradients and amounts of pollen remaining airborne can only be approximations and must be viewed with caution. Similarly the implications for pollination of concentrations of pollen airborne at distance from the source must be assessed in the context of pollen viability and other factors such as competition from pollen produced by the receptor stand.

It is important to appreciate that the results of limited experimental data from one area may not represent the prevailing situation in another location and climate. Similarly the data derived from theoretical models should be used only as guidelines with acknowledgement of the assumptions made. In order to provide realistic estimates of pollen transport distances in particular cases local variables need be considered including the prevailing climate and topography. In the following sections the literature relevant to making estimates of maize pollen transport from plots is considered both for pure stands and for plots with mixed planting of GM and ordinary maize.

4.2 Dispersal within stands

Available evidence indicates that total deposition within the source plot is greater than that outside (Raynor et al. 1972) but there will always be some dispersal beyond the borders of the plot. In situations where GM maize is planted within plots such as in rows bordered by ordinary maize it is useful to consider the relative contributions that the plants make to the concentration of pollen emanating from the edge of the crop. Evidence for this comes from studies of dispersal within the crop stands. Paterniani and Stort (1974) conducted trials using one central plant with dominant yellow endosperm colour in each of 4 plots of white endosperm maize ranging in size from 15 x 20 m to 40 x 40 m. The plants were harvested individually and the seeds of each type counted. The mean percentages of pollination by the central plant in relation to increased distances were calculated. The findings indicate a panmitic population in which male gametes are considerably mixed within the stand. At distances between 10 to 20 m the mean percentage pollination by the central plant is 0.01% decreasing to 0.005% at 30m. This rate remains fairly constant with increasing distance to the edge of the field. The greatest amount of pollination occurs in proximal plants. The results indicate that 50% of the kernels of any individual plant result from pollen of plants within a radius of about 12m. This involves about 800 to 2500 plants. The remaining 50 % must obviously come from pollen further afield. The authors state that iAuWhat is surprising is that after some distance the amount of pollination even though small at about a few kernels per 100,000 seeds remains reasonably constant up to the borders of the fields which is about 170 plants from the central oneiAu. Clearly pollen from the central plant could travel to the edges of the plot despite the filtering and impact effects of the maize crop.

If GM maize is grown within a stand of ordinary maize the maximum contribution that GM plants could make to the pollen flow from the mixed stand would be in the ratio of the plants grown. This could be considerably less depending on the planting scheme but would not decrease to zero even if there were only a few GM plants and these were in the centre of the plot.

4.3 Dispersal downwind from stands

To some extent studies have produced contradictory results but there is general agreement that the typical downwind dispersal pattern of maize pollen by the airflow in low to moderate wind speeds results in a relatively steep deposition gradient. This would be expected as the dispersion of corn pollen is influenced by its large size and rapid settling rate. Maize pollen is one of the largest normally dispersed by the wind from a low level source and compares in size to the largest particles commonly airborne ( Raynor et al. 1972).

Published results of measurements of the deposition gradients differ considerably. One point of comparison is the measure of the half distance that is the distance over which the concentration decreases by half as the distance from the source increases by a constant increment (the half distance). This figure provides indications of decay rates but has limitations and should not be extrapolated to distances outside the observed range. Some studies report short half distances. For instance the work of Bateman (1947) gives a figure of 3.77m. He describes experiments showing that contamination from cross pollination of different maize cultivators may drop by 99 per cent over a distance of 12 to 15m. Similarly the work of Hodgson (1949) indicates a steep decay deposition curve with a half distance of 8.25 m. In comparison Jones and Newell (1948) report data showing a half distance of 47.47m indicating a potential for cross pollination over several hundred metres.

Estimates of half distances have been applied in dispersal models. These make numerous assumptions about the features of dispersal but they have proved useful in some cases for describing natural and experimental gradients generally within a few hundred metres of the source under certain weather conditions. For instance Fitt et al. (1987) used data published on pollen dispersal from various crops to develop power law and exponential models, achieving a high percentage of explanation of variance (r2). The greatest r2 maize was for data from Hodgson (1949) with a half distance of 8.25m. This indicates concentrations at 50 m being less than 1% of that at 1m from the crop edge. However using data from Jones and Newell (1948) in the same model but with a half distance of 47.47m in this case, the concentration at 500 m is estimated to be 0.05 % of that at 1m from the crop. McCartney (1994) also uses the maize pollen I/2 distance of 47m in a negative exponential relationship with similar results.

All models have limitations as they are essentially descriptive, not interpretative and should not be extrapolated outside the observed range. The exponential model applies to particle dispersal when the decrease in concentrations with distance away from the source is predominantly from deposition. For maize pollen there will always be some dilution and diffusion within the airflow that will distort deposition rates so that the model will not be entirely accurate. The processes involved in particle dispersal are very complex making it impossible to describe gradients in a model using a single parameter. For instance deposition rates do not indicate ambient concentrations of the fractions remaining. Factors such as frictional turbulence and thermal convection which can cause steep deposition gradients can transport large numbers of pollen grains to great heights where they can disperse over long distances (see section 6).

Some workers have used bi-axial gaussian dispersion models using estimates of standard deviations of dispersion gradients taken from Pasquill (1971). Gaussian models are not appropriate in the case of maize pollen because they assume that the concentration of the particles is normal about a central axis. Dispersion in the vertical axis is unlikely to be even for maize pollen due to the weight of the pollen grains. For example Raynor et al. (1972) found that vertical dispersion patterns were more flattened in the case of maize pollen than with Timothy grass or ragweed. Their results demonstrated that the rate of settling opposes the rate of upward dispersion so that the height of pollen plume does not increase continuously with downwind distance. Similarly dispersion in the cross wind axis is unlikely to be even because the grains may not take up the motion of eddies.

One of the most detailed studies on maize pollen dispersal was that conducted by Raynor, Ogden and Hayes (1972). Dispersion and deposition of corn pollen emitted from plants in two 18m diameter plots were studied in 39 tests. Concentrations were measured by wind impaction samplers mounted at four heights from 0.5 to 4.6m and at five distances from the source on 20 degree radii extending to 54.9m downwind in 1963 and 59.5m in 1964. Deposition was measured by greased microscope slides on the ground. The study indicated at 60m from the source the total amount of pollen remaining airborne was about 5% of that at 1m from the source and that the deposition per unit area at this distance downwind was only 0.2% of that near the source. In the trials by Raynor et al. attenuation of airborne maize pollen grains between the source and 60m was 50:1 whereas attenuation of deposition was 2500:1. This much heavier deposition near to the source corresponds to the grains that never became effectively airborne. This point is relevant when considering data based on deposition readings. Taking concentrations at 1m as 100% the mean results of 15 samples indicated concentrations at 54.9m to be 1.3% (SD 3.30) and at 59.5m to be 1.1% ( SD 2.1).

In contrast the results from Jones and Newell (1948) show approx. 1% concentrations remaining at 427m and those from Jones and Brooks (1950) approximately 0.75% at 503 m. It is likely that these shallower slopes of the deposition curves result from greater source areas and the greater wind speed occurring during their work. Faster winds would result in dispersal over larger distances but they would also cause more depletion by impaction. The range of weather conditions during the trials by Raynor et al ( 1972) were small and did not vary enough to permit documentation of the effects of wind speed.

In most of the data on maize pollen dispersal from empirical studies the loss in air concentrations compared with deposition are uniformly high indicating an over estimate of deposition or an underestimate of air concentrations. Monteith (1975) proposes that the peak concentrations are not adequately estimated. He suggests that the poor retention efficiency of samplers for corn pollen may be enough to cause errors in computing concentrations. The wide range of estimates for deposition rates coupled with the narrow range of weather conditions explored and the possible errors involved in monitoring bring in to question the validity of the results.

More reliable information on potential spread of pollen comes from observations of outcrossing. For example Jones and Brooks (1950) researched the effectiveness of distance and border rows in preventing outcrossing in corn. In one of three years the outcrossing exceeded the maximum mixture permitted by international standards at distances of 300m isolation . At a distance from the contaminating field of 400m the mean percent outcrossing was 0.42 and at 500 m the mean percent outcrossing was 0.32. Other cited levels of cross breeding between maize at various distances include Jones and Newell (1948) 7.2% at 250m, Jones and Brooks (1950) 2.47% at 200m and Salamov (1940) 0.21% at 805m.

5. ESTIMATES OF POLLEN TRANSPORT BY THE WIND IN THE VICINITY OF THE CROP AND RATES OF CROSS POLLINATION

The publications described in section 4 have produced statistics that have lead many workers to report that an isolation distance of 200 to 400 metres is considered satisfactory ( Airy 1955). However most studies have been done in low to moderate wind speeds so insufficient evidence is available from empirical studies to allow the prediction of the features of maize pollen transport in a variety of weather conditions. In gusty weather, deposition gradients near to crops may be steeper but that of the distance travelled above crops may be enhanced ( McCartney 1990 b ). In general higher wind speeds result in longer travel distances for pollen but the increased turbulence leads to greater impaction.

Taking the evidence of published trials and use of data in dispersion models described previously, estimates can be made of the transport of maize pollen in low to moderate wind speeds . However little confidence is attached to these due to the reasons outlined in section four. In the following section the pollination due to pollen from one maize plot ( the donor plot) is considered for plants in another plot (the receptor plot ). Based on consideration of the limited evidence available the generalised estimate figures for maize pollen concentrations from the donor plot at downwind distances under dry weather conditions with low to moderate wind speed are as follows: ( expressed as percentages of concentrations at 1m from the source, Qd ):

Table 2 . Estimates of percentages of pollen concentrations at various distances downwind compared with those at 1m from the source ( based on evidence presented in section 4).

60m from the crop edge would be approximately 2%

200 m downwind from the source would be approximately 1.1%

500m it would be approximately 0.75 % to 0.5 %

These relatively small percentages could still result in considerable concentrations in the receptor plot due to the large amounts of pollen released from maize. If it assumed that there was no competing pollen being released from within the receptor plot these amounts could result in high rates of cross pollination. For example if the figures quoted in 3.1 are considered, a conservative estimate of pollen production per plant is in the order of 25 million grains. This could result in the following approximate amounts of pollen per plant in the donor plot being available for pollination in the receptor plot over the duration of pollen release. Obviously the amounts would not be consistent for all plants in the plot as there would be some deposition and filtering within the stand. Plants on the edge of the plot could contribute most of their pollen to the airflow leaving the crop.

Table 3. Possible numbers of pollen grains remaining air borne from an individual plant at various distance downwind (based on estimates of 25 million grains produced per plant).

500,000 at 60 m

275,000 at 200m

187,500 to 125000 at 500m

However in order to arrive at a realistic estimate of the amount of cross pollination likely to occur with these percentages and amounts the following aspects need to be considered:

  1. Synchronisation of maturation of the flowers ( both male and female parts).

  2. Relative concentration strengths of the pollen produced by the donor plot and the receptor plot at the point of pollination. There may be an overlap in pollen production periods in the two stands so there may be competition for pollination between pollen from the two sources.

  3. The amount of self or cross sterility in the variety.

  4. Density of the stands.

If the donor crop releasing pollen was a mixed GM / ordinary maize plot the source strength ( Qd) could be described in terms of the ratio of the GM/ ordinary pollen (Qgm/Qn) e.g. 1:10, as this would give the maximum contribution of the GM pollen. The corresponding percentage of the concentration remaining at various downwind distances could be calculated e.g. if 10% of the stand was GM maize the concentration of GM pollen remaining at 60m downwind would be in the order of 0.2% of the total pollen concentration at 1m from the source.

If it is assumed that there is an overlap in pollen release between the two plots of maize there will be competition for pollination. The donor plot source strength (Qd) will need to be considered in relation to receptor plot source strength (Qr)

If flowering is synchronous and both stands produce equal amounts of pollen then the relative concentrations of pollen from the donor plot and the receptor plot can be considered e.g. at 60m this will be Qd x 2%: Qr giving a qualification to the probability of pollination. For instance, taking the figures from Table 2, the Qd component in the prevailing pollen concentration at the edge of a receptor plot at 60m would be 1.9%, at 200m would be 1.08% and 500m would be 0.74 to 0.49%.

At these concentration ratios the rates of cross pollination would be in the order of:

at 60 m 1 kernel per 53

at 200 m 1 kernel per 93

at 500 m 1 kernel per 135 to 204

If GM maize is grown within the donor plot the corresponding figures for the contributions that its pollen makes to the amounts at the receptor plot can be calculated from the ratios of GM to ordinary maize in the donor plot.

These estimates should be considered as rough guidelines only as they would be altered by factors such as climatic conditions which effect the transport of pollen, and the numbers of bees and other insects around, which would be likely to increase the amounts of pollen transfer. Also the generalised predictions based on empirical evidence and theoretical models would need to be modified in relation to local topography and climate, and the sizes and lay-outs of the plots. The estimates given in this section are for conditions of low to moderate wind speeds. In higher wind speeds with gusty conditions the maize pollen dispersal will be different. Some grains are likely to travel further downwind but impaction rates will also increase. More empirical work needs to be done to investigate the details of dispersal under these and other weather patterns.

6. POTENTIAL LONG RANGE DISPERSAL

In certain weather conditions particles, including pollen grains, can travel long distances on the airflow. Long-distance dispersal of maize pollen needs to be considered within the constraint of its viability time ( in the region of 24 hours under normal weather conditions, Purseglove, 1972). The following section indicates that maize pollen can travel for long distances within its viability period, given the right conditions for doing so.

Maize pollen is relatively large and heavy (section 3). Empirical work on its dispersal has indicated relatively steep declines in concentrations with distance away from the source and limited upward spread of the plume (see section 4 ). However these studies have investigated dispersal only to heights of c. 4.6 m above ground in the downwind direction and to distances of c. 500m maximum downwind. The studies have been conducted in a narrow range of weather conditions. No work has been done specifically on the movement of maize pollen in convection currents, or on movement aloft in turbulent conditions or during the passage of weather fronts. Research done on the dispersal of other pollen types has demonstrated that long range transport does take place including pollen from low level sources.

Vertical transport of pollens takes place by several mechanisms. On warm days with low wind speeds convective currents driven by the heating of the ground by the sun lead to mixing through the boundary layer. This activity has a marked diurnal influence with particles being dispersed laterally through convection cells during the day, and descending when the convection subsides ( Oke 1978). As long as there is a positive convective air movement the net result will be to keep pollen in the atmosphere. Settling out of pollen usually occurs during cooling in the evening when the majority of grains will return to the surface.

Most anemophilous pollen will be liberated during day time in dry, warm weather. Days like this usually have thermals rising turbulently that will have a positive effect in bringing pollen grains up into the higher strata. The upper limit for convective ascent is marked by the thermal inversion, often shown by the presence of cumulus clouds. Convective cells are typically 1 -3 km in diameter, reaching some 1-2,000 m in height and last about 20 to 30 minutes each, during which time they can move downwind. The individual cells may form composite cells 5-10 km across and last for several hours. Upward velocity of cell tops reaches 0.5-1.5m/sec and horizontal expansion of 0.5-1.0 m/sec ( Hardy and Ottersten 1968 ). Some pollen grains will have reached the inversion layer when the bubble collapses. It may then be transported horizontally considerable distances depending on weather conditions. During the evening and night time convection will cease and the pollen will tend to fall towards the ground but this may be impeded by low level inversions. The usual length of time available for pollen to travel as it is kept aloft by convection is a maximum of one day. This would be equivalent to a distance of about 50 - 180 km, although it is well known that much longer transports do occasionally take place (Faegri & Iversen, 1989) when suitable meteorological conditions occur.

On days with less solar heating and higher wind speeds, pollen can be dispersed vertically by turbulence generated either by instability in the lapse rate or by rough surfaces such as uneven topography. Biological particles introduced into the boundary layer have been observed in detectable concentrations to distances of several hundred kilometres downwind ( e.g. Hjelmroos 1991). Penetrative transport to great heights can also take place through updraughts generated by deep intense convective storms. In such storms large masses of air, originally lying near the surface, are transported in a few tens of minutes to heights typically of the order of 8 to 12 km. At such heights, in the middle latitudes, winds are often very strong, in the range 25 to 50 m per second, so that pollen can travel great distances in a matter of hours (Mandrioli et al. 1984).

Hirst and Hurst (1967) sampled air for pollen and spores over the north seas. Their results include a case in which a pollen cloud generated over Britain could later be found as a pollen concentration cloud over the North Sea. Pollen released during one day was found the following day 300-400 km off the coast. Transport took place over the sea where dispersal conditions could be different from those over land depending on the weather. For example pollen transport over land could be enhanced by increased convection but conversely the concentrations could be depleted by more deposition due to turbulence. Tyldesley (1973) found appreciable quantities of arboreal pollen (up to 30 per m3) in the air in the treeless Shetlands, 250-380 km away from the nearest forests, in connection with favourable meteorological conditions, i.e. cyclonic storms.

A frontal storm can lift air masses several kilometres up in the air in a very short time and thus place pollen grains far above the day and night cycle (Faegri & Iversen, 1989). Once pollen has arrived in the upper atmosphere it can travel for many hundreds of kilometres on the airflow until finally being deposited or it may be captured by water drops and return to the surface in precipitation (Mandrioli, 1984). In general long range transport occurs most efficiently in dry conditions with limited mixing depth and moderate to high wind speeds.

Pollens can also be re-suspended from surfaces in gusts of wind and re-deposited. For example, Erdtman (1938) described finding Zea pollen in the air in Sweden during midwinter (Faegri & Iversen, 1989). If re-suspension took place within the time of pollen viability it could extend the effective transport distance.

It is reasonable to assume that maize pollen can remain viable and capable of effective fertilisation for at least 24 hours in most weather conditions prevailing in the UK (2. 1). This means that with mean horizontal wind speeds of 2 m/s, that can occur on summer days with convection currents that could keep the pollen grains aloft (section 7), they could travel I km in 4.16 minutes, 7.2 km in an hour (potentially 172.8 km in a day). In wind speeds of 10 m/s some pollen grains would travel greater downwind distances before deposition than in slower wind speeds. Winds of 10 m/s would give rise to turbulent conditions in the boundary layer keeping some pollen airborne for longer than in non turbulent air flows. If the pollen remained airborne it could travel 36 km in an hour and nearly 864 km in 24 hours.

7. THE TRANSFER OF MAIZE POLLEN BY BEES AND OTHER INSECTS

Zea mays is generally regarded as being anemophilous (successful pollination relies on wind dispersal of pollen) but maize pollen is also collected by bees and may be transported by flies. Maize pollen is not uncommon in honey but would not be the major pollen type. There is often 90% of one main type and a 10% mix of many different species, which does contain some wind-pollinated types such as grass and maize ( Hodges 1984). Bees may pick up maize pollen whilst out foraging for a better source in perhaps a hedgerow (personal communication, Ms Sarah Brookes, Manager of the Bee Unit, Luddington, Warwickshire for 13 years, and Mr Paul Wilkins The National Bee Unit, Central Science Lab, National Bee Unit, Sand Hutton, York. YO41 1LZ ).

Evidence that maize pollen is collected by bees is available from experimental results and monitoring (Percival 1947, 1955, Nowakowski and Morse 1982, Vaissiere and Vinson 1994). Nowakowski and Morse from the Department of Entomology, Cornell University, New York, conducted research on honey-bee behaviour in sweet-corn fields to help minimise effects of insecticide spraying on foraging bees. They state that,iAuAlthough corn is wind pollinated it produces such copious amounts of pollen that it is highly attractive to bees, both honey bees and a wide variety of solitary bees.

Vaissiere and Vinson (1994) report the use of maize pollen, amongst others, in laboratory conditions to test the effectiveness of honey bee pollen collection. They note that maize pollen was readily collected by nearly all of the bees in the experiment, however, as the bees had been starved of pollen for a week this may not give a true representation of natural behaviour. Although reference is made to bees collecting maize pollen in the open this activity would be governed by a number of factors such as distance from hive and availability of more nutritious food sources. Percival (1947) notes that iAuany plant offering a fair amount of pollen per flower-form will be worked for pollen by the honey-bee, provided that (a) it grows within 1/4 mile of the hive, and (b) it attains a reasonable density.

Miller (1985) describes how bees may be used for collecting maize pollen. Once the bees have collected the pollen in their normal manner, the pollen is then collected from the bees and used. However, it has been noticed that some biochemical alterations can occur in pollen collected by bees.

Percival conducted work in the 1950s to investigate why honey bees collected some types of pollen more than others and Zea mays was included in the 86 species she studied (1955). She discovered that Z. mays presented pollen between 0700 hrs and 1800 hrs but that approximately 40% of the daily amount was produced between 1000-1100 hrs. She also found that in Z. mays all the anthers in one flower dehisce simultaneously.

Percival conclusions were strengthened by research by Maurizio (1951) who showed that bee colonies had a need for pollen in early spring but that nectar was more desirable in June/July. Maurizio had also discovered that some pollen types were extremely important to bees. Z.mays was amongst the pollens that were found to iAustimulate the development of brood food glands, ovaries and the fat body and also prolong length of life. This means that bees could be actively choosing certain pollen types not simply being attracted to quantity and proximity. Percival managed to calculate the amount of pollen produced per flower-form for maize and found it to be 494 mg in total, 16 mg per day. This is a considerable amount of pollen, as might be expected for a wind-pollinated plant. Its attraction to bees would seem to be mostly due to its biological value because it flowers at a time when there is no shortage of other pollen around and maize does not produce nectar. Z. mays has a peak of pollen production at a time of day which is usually warm enough for insect activity.

Problems encountered in trying to estimate the distance of insect-carried pollen travel are discussed in a paper by Richards and Ibrahim (1978). Work on Primula veris found that pollen travel increased in fine, warm weather and attributed this to increased pollinator activity. This could be due to foraging time extending into evening hours on warm, dry days. Estimates on the distance bees will travel to find pollen or nectar differ. Early estimates tended to give relatively short distances e.g. Carter (1946) considers an economical flight for a honey-bee to be about 1 mile (at speeds of approximately 12-15 m.p.h.), Hooper gives a distance of about 1.5 miles (1976). Morse ( 1972) agrees with this for the majority of pollen collection but says that a bee might travel up to 8 or 9 miles if necessary. More recently it has been widely accepted that bees will regularly travel about 3 miles from the hive but will not go this far if a good source of pollen is available closer ( pers. com. Ms Sarah Brookes, and Mr Paul Wilkins).

In addition to transport by bees it is likely that occasional random encounters with other insects could lead to the transfer of maize pollen to neighbouring fields. Research into this topic has found evidence to support this hypothesis. Work carried out on Plantago lanceolata by Stelleman (1978) showed that despite being considered anemophilous, the flowers were frequently visited by certain flies. This in itself was not proof of pollination but trials with marked pollen, reported in this paper, showed that it was being transported from one inflorescence to another. The belief that some species use both wind and insect pollination is widely accepted (e.g. Proctor 1978) . The extent to which one method or the other is used cannot be taken for granted and must be discovered by observation and experiment.

8. DISCUSSION AND CONCLUSIONS

8.1 Empirical work and estimates of pollen dispersal downwind from plots.

Most empirical work on maize pollen dispersal has been done under a limited range of weather conditions and for relatively short distances downwind. In some cases the use of the results is further constrained by errors in sampling and in others the data have been applied to inappropriate dispersion models. The published estimates of deposition gradients give a wide range of readings but it is reasonable to assume from the features of the pollen grains that the deposition gradients would be steep in low to moderate wind speeds ( section 4.3). Estimates of airborne concentrations remaining at distances from the source are more problematic due to lack of reliable data. However it is reasonable to assume that concentrations of pollen remaining airborne downwind from the source would be more attenuated in high wind speeds.

Evidence from patterns of pollen dispersal within crop stands shows that pollen from central plants contributes to the pollen stream leaving the crop edge.

Considering the lack of empirical evidence it is not realistic to give exact predictions of maize pollen dispersal. Estimates have been given in section 4.3 based on available information. However these are qualified with a statement of low confidence because of the poor quality of the information base.

The information available indicates that in low to moderate wind speeds the percentages of pollen concentrations remaining airborne compared with those at 1m from the source would be approximately 2% at 60m, 1.1% at 200 m and approximately 0.75 % to 0.5 % at 500m. The implications of these amounts for pollination are discussed in section 4.3.

8.2 Movement by Bees and other insects.

The spread of pollen by the wind would be enhanced by transport by bees and other insects. Research has shown that Bees regularly visit maize flowers and transport maize pollen. Bees could move maize pollen several miles from the crop each day in suitable weather. Evidence shows that significant amounts of pollen are involved but it is not possible to quantify this component from published data found in searches so far.

8.3 Long range transport

Substantial evidence exists for long range transport of considerable numbers of pollen grains especially under the influences of movement in convective cells or in frontal storms. It is probable that notable amounts of maize pollen are transported by these mechanisms for several kilometres and that decreasing amounts are carried further with exceptional events giving rise to transport of hundreds of kilometres. Maize pollen remains viable under normal conditions for approximately 24 hours giving potential for pollination by grains that had travelled many hundreds of kilometres on the airflow.

8.4 Assessments of pollen flow from Maize.

Evidence currently available from empirical studies is insufficient to allow accurate assessments to be made of maize pollen dispersal under the different weather conditions prevailing in the UK during the maize pollen season. In any assessment of pollen flow from maize plots consideration should be given to the limitations of evidence from empirical studies and from the results obtained using theoretical models. In addition acknowledgement must be given to the potential movement of maize pollen by bees and the possibilities of long range transport under certain weather conditions. Overall it is clear that maize pollen spreads far beyond the 200m metres cited in several reports as being an acceptable separation distance to prevent cross pollination.

9. REFERENCE LIST

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  2. Bateman AJ, 1947. Contamination of seed crops. II. Wind pollination. Heredity I: 235-46
  3. Carter GA. 1946. The Hive Bee. Littlebury & Company Ltd. Worcs.
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  11. Goss JA. 1968. Development, physiology and bio-chemistry of corn and wheat pollen. Bot. Rev. 34: 333-358.
  12. Hardy KR & Ottersten H. 1968. Two scales of convection in the clear atmosphere. Proc. Int. Conf. Cloud phys. Toronto: 534-538 (Am. Meteorol. Soc.).
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  14. Hjelmroos M, 1991. Evidence of long-distance transport of Betula pollen. Grana, 30: 215-228
  15. Hodges D. (1984) The pollen loads of the honey bee. International Bee Research Association, London.
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  18. Jones MD & Brooks JS. 1950. Effectiveness of distance and border rows in preventing outcrossing in corn. Oklahoma Agricultural Experimental Station - Technical bulletin No 38
  19. Jones MD and Newell LC. 1948. Longevity of pollen and stigmas of grasses: Buffalograss, Buchloe dactyloedees (NUTT) Engelm., and corn, Zea mays L. Journal of the American Society of Agronomy, 40 (3): 195 - 204
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  24. Maurizio A. 1951. Untersuchungen uber den Einfluss der Pollenernahrung und Brutpflege auf die Lebensdauer und den physiologischen Zustand der Bienen. Report of the XIVth Int. Beekeeping Congr. P. 320. Leamington Spa.
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  26. Dispersal in Agricultural Habitats (Eds. Bunce and Howard) pp 133-158.
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  30. Monteith JL. 1975. Vegetation and the Atmosphere. Academic Press
  31. Miller PD, 1985. Maize Pollen: Collection and Enzymology. Chapter 45, pp 279-282. In: Sheridan WF (ed.). 1985. Maize for Biological Research. A Special Publication of the Plant Molecular Biology Association, USA.
  32. Morse RA. 1972. The Complete Guide to Beekeeping. Pelham Books.
  33. Nowakowski J and Morse R. 1982. The behaviour of honey bees in sweet corn fields in New York state. American Bee Journal, January: 13-16.
  34. Oke TR. 1978. Boundary layer climates. Methuen, London.
  35. Pasquill F. 1974. Atmospheric Diffusion, 2nd ed.- Ellis Horwood, Chichester.
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  37. Percival MS. 1947. Pollen collection by Apis mellifera. New Phyto. 46: 142-165.
  38. Percival MS. 1950. Pollen presentation and pollen collection. New Phyto. 49 : 40-63.
  39. Percival MS. 1955. The presentation of pollen in certain angiosperms and its collection by Apis mellifera. New Phyto. 54: 353-368.
  40. Pfundt M. 1910. Der Einfluss Der Lufteuchtigeit Auf Die Lebensdauer Des Blutenstaubes. Jahrb. Wiss.Bot., 47:1-30.
  41. Proctor MCF. 1978. Insect pollination syndromes in an evolutionary and ecosystematic context. In: Richards AJ (Ed.), 1978. The Pollination of Flowers by Insects. Academic Press.
  42. Purseglove JW. 1972. Tropical Crops. Monocotyledons 1. Longman Group, London.
  43. Raynor GS, Ogden EC, and Hayes JV. 1972. Dispersion and Deposition of Corn Pollen from Experimental Sources. Agronomy Journal, 64: 420 iAi 427
  44. Raynor GS, Ogden EC and Hayes JV. 1973. Dispersion of Pollens from Low-Level, Crosswind Line Sources. Agricultural Meteorology. 11: 177 - 195.
  45. Richards AJ & Ibrahim H, 1978. Estimation of neighbourhood size in two populations of Primula veris. In: Richards AJ (Ed.), 1978. The Pollination of Flowers by Insects. Academic Press.
  46. Salamov AB. 1940. About isolation in corn. Sel.i.Sem, 3. (Russian translation by Michel Atanasiev in 1949).
  47. Smith EG. 1990. Sampling and identifying allergenic pollens and molds. Blewstone Press, Texas.
  48. Stelleman P, 1978. The possible role of insect visits in pollination of reputedly anemophilous plants, exemplified by Plantago lanceolata, and syrphid flies. In: Richards AJ (Ed.), 1978. The Pollination of Flowers by Insects. Academic Press.
  49. Tyldesley JB, 1973. Long-range transmission of tree pollen to Shetland. I-III. New Phytologist. 72: 175-190, 691-697
  50. Vaissiere B and Vinson SB. 1994. Pollen morphology and its effect on pollen collection by honey bees, Apis mellifera L. (Hymenoptera: Apidae), with special reference to upland cotton, Gossypium hirsutum L. (Malvacaece). Grana. 33 : 128-138.
Additional relevant publications not referred to in text.

10 (a) SEARCHES COMPLETED

Internet - Search engine: Yahoo Key words: Maize Pollen and Maize + Pollen

CD Rom - Medline Key words: Maize, pollen, dispersal (combinations of)

Ecological abstracts: 1977 -1998 inc. Key words: Maize, pollen, pollination, corn, Zea mays

University of Birmingham - On-line Catalogue Key words: Maize, pollen, dispersal, crop research (and combinations of)

University College Worcester - Library catalogue Key words: Maize, pollen, dispersal, crop, bees

The Bee Unit Mr Paul Wilkins The National Bee Unit, Central Science Lab, National Bee Unit, Sand Hutton, York. YO41 1LZ.

Allergon , Valinge 2090 S- 26292 Angelholm Sweden (Suppliers of pollen)

10( B) MAIZE POLLEN DISPERSAL: WEB SITES OF INTEREST

http://192.100.189.65/cimmyt/Informationservices/publications/vol.... Scientists announce a breakthrough in research on sexual maize.

http://plantbio.berkeley.edu/~nigel/Poster/abstract.html Transposable genetic elements-maize.

http://madcow.newscientist.com/ns/980801/ncrops.html New Scientist Planet Science: Up to their necks in it .

http://www.cenargen.embrapa.br/binas/Library/ucs/index.html Perils amidst the promise - Ecological Risks of Transgenic Crops in a Global Market.

http://www.maff.gov.uk/inf/newsrel/ACNFP/ACNFP4.HTM Government clearance for new lines of genetically modified maize.

http://www.bats.ch/data/english/k3a44.htm The risk of vertical gene flow caused by transgenic crops in Switzerland.

http://www.cenargen.nature.com/cgi-bin/search.cgi Soil Association

Bristol House, 40-56 Victoria Street, Bristol BS1 6BY T: 0117 929 0661 F: 0117 925 2504 E: info@soilassociation.org W: www.soilassociation.org

Updated: 02/03/1999


Top PreviousNextFront Page

Date: 25 Mar 2000 14:00:18 U
From: "j.e. cummins" jcummins@julian.uwo.ca

USDA and Delta and Pine against the World Inventors

New terminator patent: US5723765: Control of plant gene expression

Sections:
Inventors:
Applicant(s):
BACKGROUND OF THE INVENTION
SUMMARY OF THE INVENTION

Inventors:

Oliver; Melvin John , Lubbock, TX
Quisenberry; Jerry Edwin , Idalou, TX
Trolinder; Norma Lee Glover , Quanah, TX
Keim; Don Lee , Leland, MS

Applicant(s):

Delta and Pine Land Co., Scott, MS
The United States of America as represented by the Secretary of Agriculture, Washington, DC

BACKGROUND OF THE INVENTION

This invention relates to certain transgenic plants and involves a method of creating transgenic plants with controllable genes. More particularly, the invention relates to transgenic plants that have been modified such that expression of a desired introduced gene can be limited to a particular stage of plant development, a particular plant tissue, particular environmental conditions, or a particular time or location, or a combination of these situations.

Various gene expression control elements that are operable in one or more species of organisms are known. For example, PCT Application WO 90/08826 (Bridges, et al.) discloses an inducible gene promoter that is responsive to an exogenous chemical inducer, called a "gene switch." This promoter can be linked to a gene and introduced into a plant. The gene can be selectively expressed by application of the chemical inducer to activate the promoter directly.

PCT application WO 94/03619 (Bright, et al. discloses a gene cascade consisting of a gene switch linked to a repressor gene and a repressible operator linked to a disrupter protein capable of disrupting plant development. Growth of the plant can be controlled by the application or withholding of a chemical inducer. While the inducer is present, the repressor is expressed, the promoter attached to the disrupter gene is repressed, the disrupter protein is not expressed, thereby allowing the plant to grow normally.

If the chemical inducer is withheld, the gene switch is turned off, the repressible promoter is not repressed, so the disrupter protein is expressed and plant development is disrupted. This system is said to be useful for controlling the escape of plants into the wild by making their continued growth and development dependent on the continued application of a chemical inducer, and to mitigate the problem of preharvest sprouting of grains by withholding the chemical inducer at the last stages of seed development.

Gatz and Quail (1988) and Gatz, et al. (1992), (Hoppe-Seyler), 372:659-660 (1991), disclose a plant-active repressor-operator system that is controlled by the application of tetracycline. The system consists of the Tn10 tet repressor gene, and a cauliflower mosaic virus (CaMV) 35S promoter, modified to contain two tet operons and linked to the chloramphenicol acetyltransferase (cat) gene (Gatz and Quail, 1988), or modified to contain three tet operons and linked to the beta-glucuronidase (gus) gene (Gatz, et al., 1992). So long as the Tn10 tet repressor gene is active, the modified promoter is repressed by the interaction of the repressor with the tet operons, and the cat or gus gene is not expressed. The presence of tetracycline inhibits repressor binding, enabling expression of the cat or gus gene.

SUMMARY OF THE INVENTION

The present invention involves, in one embodiment, the creation of a transgenic plant that contains a gene whose expression can be controlled by application of an external stimulus. This system achieves a positive control of gene expression by an external stimulus, without the need for continued application of the external stimulus to maintain gene expression. The present invention also involves, in a second embodiment, the creation of transgenic parental plants that are hybridized to produce a progeny plant expressing a gene not expressed in either parent. By controlling the expression of genes that affect the plant phenotype, it is possible to grow plants under one set of conditions or in one environment where one phenotype is advantageous, then either move the plant or plant its seed under another set of conditions or in another environment where a different phenotype is advantageous. This technique has particular utility in agricultural and horticultural applications.

In accordance with one embodiment of the invention, a series of sequences is introduced into a plant that includes a transiently-active promoter linked to a structural gene, the promoter and structural gene being separated by a blocking sequence that is in turn bounded on either side by specific excision sequences, a repressible promoter operably linked to a gene encoding a site-specific recombinase capable of recognizing the specific excision sequences, and a gene encoding a repressor specific for the repressible promoter whose function is sensitive to an external stimulus. Without application of the external stimulus, the structural gene is not expressed. Upon application of the stimulus, repressor function is inhibited, the recombinase is expressed and effects the removal of the blocking sequence at the specific excision sequences, thereby directly linking the structural gene and the transiently-active promoter.

In a modification of this embodiment, the sequences encoding the recombinase can be introduced separately into the plant via a viral vector.

In an alternative embodiment, no repressor gene or repressible promotor is used. Instead, the recombinase gene is linked to a germination-specific promotor and introduced into a separate plant from the other sequences. The plant containing the transiently-active promotor, blocking sequence, and structural gene is then hybridized with the plant containing the recombinase gene, producing progeny that contain all of the sequences. When the second transiently-active promotor becomes active, the recombinase removes the blocking sequence in the progeny, allowing expression of the structural gene in the progeny, whereas it was not expressed in either parent.

In still another embodiment, the recombinase gene is simply linked to an inducible promoter. Exposure of the plant to the induce specific for the inducible promoter leads to the expression of the recombinase gene and the excision of the blocking sequence.

In all of these embodiments, the structural gene is expressed when the transiently-active promoter becomes active in the normal course of growth and development, and will continue to be expressed so long as the transiently-active promoter is active, without the necessity of continuous external stimulation. This system is particularly useful for developing seed, where a particular trait is only desired during the first generation of plants grown from that seed, or a trait is desired only in subsequent generations.


Top PreviousFront Page

Date: 25 Mar 2000 14:22:36 U
From: "j.e. cummins" jcummins@julian.uwo.ca

USDA and Delta and Pine against Civilization

patent US5977441: Control of plant gene expression

Sections:
Inventor(s):
Applicant(s):
BACKGROUND OF THE INVENTION
SUMMARY OF THE INVENTION

Inventor(s):

Oliver; Melvin John , Lubbock, TX
Quisenberry; Jerry Edwin , Idalou, TX
Trolinder; Norma Lee Glover , Quanah, TX
Keim; Don Lee , Leland, TX

Applicant(s):

Delta and Pine Land Company, Scott, MS
The United States of America as represented by the Secretary of Agriculture, Washington, DC

Background/Summary:

BACKGROUND OF THE INVENTION

This invention relates to certain transgenic plants and involves a method of creating transgenic plants with controllable genes. More particularly, the invention relates to transgenic plants that have been modified such that expression of a desired introduced gene can be limited to a particular stage of plant development, a particular plant tissue, particular environmental conditions, or a particular time or location, or a combination of these situations.

Various gene expression control elements that are operable in one or more species of organisms are known. For example, PCT Application WO 90/08826 (Bridges, et al.) discloses an inducible gene promoter that is responsive to an exogenous chemical inducer, called a "gene switch." This promoter can be linked to a gene and introduced into a plant. The gene can be selectively expressed by application of the chemical inducer to activate the promoter directly.

PCT application WO 94/03619 (Bright, et al. discloses a gene cascade consisting of a gene switch linked to a repressor gene and a repressible operator linked to a disrupter protein capable of disrupting plant development. Growth of the plant can be controlled by the application or withholding of a chemical inducer. While the inducer is present, the repressor is expressed, the promoter attached to the disrupter gene is repressed, the disrupter protein is not expressed, thereby allowing the plant to grow normally. If the chemical inducer is withheld, the gene switch is turned off, the repressible promoter is not repressed, so the disrupter protein is expressed and plant development is disrupted. This system is said to be useful for controlling the escape of plants into the wild by making their continued growth and development dependent on the continued application of a chemical inducer, and to mitigate the problem of preharvest sprouting of grains by withholding the chemical inducer at the last stages of seed development.

Gatz and Quail (1988) and Gatz, et al. (1992), (Hoppe-Seyler), 372:659-660 (1991), disclose a plant-active repressor-operator system that is controlled by the application of tetracycline. The system consists of the Tn10 tet repressor gene, and a cauliflower mosaic virus (CaMV) 35S promoter, modified to contain two tet operons and linked to the chloramphenicol acetyltransferase (cat) gene (Gatz and Quail, 1988), or modified to contain three tet operons and linked to the beta-glucuronidase (gus) gene (Gatz, et al., 1992). So long as the Tn10 tet repressor gene is active, the modified promoter is repressed by the interaction of the repressor with the tet operons, and the cat or gus gene is not expressed. The presence of tetracycline inhibits repressor binding, enabling expression of the cat or gus gene.

SUMMARY OF THE INVENTION

The present invention involves, in one embodiment, the creation of a transgenic plant that contains a gene whose expression can be controlled by application of an external stimulus. This system achieves a positive control of gene expression by an external stimulus, without the need for continued application of the external stimulus to maintain gene expression. The present invention also involves, in a second embodiment, the creation of transgenic parental plants that are hybridized to produce a progeny plant expressing a gene not expressed in either parent. By controlling the expression of genes that affect the plant phenotype, it is possible to grow plants under one set of conditions or in one environment where one phenotype is advantageous, then either move the plant or plant its seed under another set of conditions or in another environment where a different phenotype is advantageous. This technique has particular utility in agricultural and horticultural applications.

In accordance with one embodiment of the invention, a series of sequences is introduced into a plant that includes a transiently-active promoter linked to a structural gene, the promoter and structural gene being separated by a blocking sequence that is in turn bounded on either side by specific excision sequences, a repressible promoter operably linked to a gene encoding a site-specific recombinase capable of recognizing the specific excision sequences, and a gene encoding a repressor specific for the repressible promoter whose function is sensitive to an external stimulus. Without application of the external stimulus, the structural gene is not expressed. Upon application of the stimulus, repressor function is inhibited, the recombinase is expressed and effects the removal of the blocking sequence at the specific excision sequences, thereby directly linking the structural gene and the transiently-active promoter.

In a modification of this embodiment, the sequences encoding the recombinase can be introduced separately into the plant via a viral vector.

In an alternative embodiment, no repressor gene or repressible promotor is used. Instead, the recombinase gene is linked to a germination-specific promotor and introduced into a separate plant from the other sequences. The plant containing the transiently-active promotor, blocking sequence, and structural gene is then hybridized with the plant containing the recombinase gene, producing progeny that contain all of the sequences. When the second transiently-active promotor becomes active, the recombinase removes the blocking sequence in the progeny, allowing expression of the structural gene in the progeny, whereas it was not expressed in either parent.

In still another embodiment, the recombinase gene is simply linked to an inducible promoter. Exposure of the plant to the induce specific for the inducible promoter leads to the expression of the recombinase gene and the excision of the blocking sequence.

In all of these embodiments, the structural gene is expressed when the transiently-active promoter becomes active in the normal course of growth and development, and will continue to be expressed so long as the transiently-active promoter is active, without the necessity of continuous external stimulation. This system is particularly useful for developing seed, where a particular trait is only desired during the first generation of plants grown from that seed, or a trait is desired only in subsequent generations.