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Sent: 10 June 2002 11:05
Subject: 29: papaya
From my work in research, I would like to discuss the complication of double fertilization mentioned by Prof. Joe Cummins (message 28, June 8)
Papaya is new in my country for the common people. In fact, it was grown long ago, but was known for medical purposes and traditional medicine and very little for research. In the last few years, papaya plantation has grown up quickly. I was interested in working on papaya breeding not only for fresh consumption, but also for employing horticultural research to serve technological processing of papaya to increase benefits for the grower. The papaya fruit is one of the richest fruits of vitamin A, C a and contains vitamin B, high starch content, changes to sugar after ripening. Papaya's green, ripe fruits and seeds are used. Papaya is found in childrens' food because of its high nutrition value or even for coloration of food products. So it is very important to study the risk of modified papaya.
The problem of papaya pollination and gene flow is the existence of different papaya types: male plants, female plants, bisexual plants (bearing hermaphrodite setting flowers) and bisexual plants (bearing male flowers and hermaphrodite long necked flowers). During my research, when I used pollen from hermaphrodite long necked flowers of male plants for pollinating female dwarf American solo flowers (I don't know is it transgenic), I obtained lemon sized papaya. I was shocked, this is unexpected. In fact the parents fruits were about 450-500 grams. And the male parent fruit (which bear one or two fruits on long sticks) was of very high quality. I say all of this to explain the great variation which will be obtained and non expected when gene flow occurs from GM to non-GM plants. [The flowering system in papaya is clearly quite complicated. The chapter on papaya in "Fruits of warm climates." by J. Morton (1987) (http://www.hort.purdue.edu/newcrop/morton/papaya_ars.html), indicates that some plants bear only female or hermaprodite (having female and male organs) flowers while others bear only male flowers. Some plants may also have both male and female flowers. Male or hermaphrodite plants may also change completely to female plants after being beheaded...Moderator].
So it is important to determine the risk and to study the effect on other populations. Research must be repeated in different parts of the world under different environments. Complete reports on crops and trees are needed in each country, even in different parts of the same country.
The farmer in my country, by his nature, selects seeds of his good plantation and keeps them until the next growing season for two reasons: i) to preserve good qualities and ii) to reduce costs of new plantings by keeping his own seeds. Honestly, I always try to follow the new technology as a researcher, but as consumer, I think more and more before eating GM food because of the fate of transgenic DNA. The haphazard usage of new biotechnology by small farmers and rich companies is fearing me also, so we need trusted people. One later question: what about future studies on transgenic DNA and preserving genetic modifications using conventional vegetative propagation of fruit trees.
Dr Aisha, A. A. Badr
Tropical Fruit Division
Alexandria Horticultural Research Station
momidic (at) hotmail.com
Sent: 10 June 2002 13:05
Subject: 30: terminology - genetic pollution
My name is Tim Roberts. I am an intellectual property lawyer, based in the United Kingdom, with some experience in plant biotechnology patenting.
Could I raise a question about terminology (always dear to the hearts of lawyers)? Some participants refer to 'genetic pollution'. Is this a scientific term, or a political one? 'Pollution' is clearly to be avoided. But other names might be used - 'genetic transfer', say, or even 'genetic donation'. Referring to 'pollution' begs the question - is recombinant gene transfer undesirable (and, if so, when)? This is convenient for opponents and awkward for apologists for the technology, but a distraction in objective discourse.
twr (at) compuserve.com
Sent: 10 June 2002 17:57
Subject: 31: Re: terminology - genetic pollution
Prof. Joe Cummins, Professor emeritus of Genetics, Canada
Webster's dictionary defines pollute: to make unhealthy, impure; to corrupt ;to make ritually unclean.
Residues of registered pesticides in food or water are considered pollution in both regulation and science. Biopesticides such as Bt toxin are essentially similar to chemical pesticides and fairly said to pollute. The common virus promoter used in most genetically modified crops (the cauliflower mosaic virus promoter) originated from a pest and on that basis fairly pollutes.
Frankly, the issue of gene modification as pollution is not really an issue of objective or colorful language - it is simply extension of plant chemotherapy to inserted transgenes. Indeed, the corporate public relations officers do love to try to impose manipulated language. For example, corporate animal producers in Canada impose the term, nutrient management, for management of manure reflecting, perhaps, their dietary habits. In the final analysis it seems best to focus on substantive issues of human and environmental safety.
Professor Joe Cummins,
University of Western Ontario.
jcummins (at) uwo.ca
Sent: 10 June 2002 17:57
Subject: 32: Re: terminology - genetic pollution
I (message 10, June 4) used "genetic pollution" to indicate a contamination of the "native" genetic pool with "foreign" DNA. No intrinsic, ethical value was implied; indeed I asked if we should consider it "good" or "bad". My usage was not meant to be political, though I can see how it could be inferred and misconstrued. Genetic pollution (contamination) used as I have intended seems concise.
John N. Nishio
Department of Botany
University of Wyoming
Laramie, WY 82071--3165
Nishio (at) uwyo.edu
Sent: 10 June 2002 17:58
Subject: 33: Re: terminology - genetic pollution
In Tim Roberts post of June 10 (message 30) he asks: "Some participants refer to 'genetic pollution'. Is this a scientific term, or a political one?"
This is not a scientific term, but rather one based upon a gut feeling and a sense of potential economic loss. Pollen has been moving by wind and animal vector since seed bearing plants evolved. For those using the marketing tool of producing 'organic' plant commodities, it is obviously a detriment to their maintenance of non-GM plant products since the organic rules in most locales/countries are unforgiving in this regard. As discussed in a post from Joe Cummins (message 28, June 8), secondary fertilization can result in detectable transgene products following gene expression in some fruits or grains pollinated by GM crops.
Although this matter has a biological basis, my feeling is that the matter will be settled in the courts in the U.S. and Canada, not through regulatory adjustment. When the U.S. Environmental Protection Agency (EPA) registers a PIP (Plant-incorporated protectant) in the U.S., as long as the gene(s) of interest has/have a food tolerance in place, there is no violation of law from cross-pollination. Food containing this transgene is legal for sale as food or feed. If the transgene(s) did not have such a tolerance under the Federal Food, Drug and Cosmetic Act, any food resulting from this cross-pollination would be considered adulterated and unfit for sale. The Food and Drug Administration would then have the authority to remove any 'adulterated' foods from shelves or feed suppliers.
One aspect of this genetic 'pollution' that I have not seen addressed is the converse of the normal argument. Namely, what about growers or breeders who expend time and money to ensure a quality seed product, with or without transgenes, and are stuck tolerating gene flow from others growing open-pollinated (more heterozygous, less uniform, less characterized) or otherwise undesirable varieties? If one spends extra money on a technology fee for a certain type of GMO seed, what loss is there when it becomes 'contaminated' with pollen from unlike varieties, whether they be organic or otherwise? It seems to me that the argument is a plausible one in either direction, it is just that the answers are not easy.
Chris A. Wozniak, Ph.D.
U.S. Environmental Protection Agency
Biopesticides and Pollution Prevention Division
1200 Pennsylvania Ave., NW, 7511C
Washington, DC 20460
703-308-7026 - fax
wozniak.chris (at) epa.gov
(Food tolerance: all pesticides associated with application in or on crops
intended for food or feed require a tolerance or exemption from the
requirement of a tolerance in order to be legally applied. A simple way to
think of this is the amount of residue allowed on a finished crop or
commodity. All PIPs to date have been granted an exemption from the
requirement of a food tolerance.
PIP -Plant-incorporated protectant: a pesticidal substance expressed within a plant and the genetic material necessary for its production. Common examples of these are cotton, corn and potato engineered to express the endotoxin from B.t. to provide insect resistance. The trait is the PIP, not the plant itself.]
Sent: 10 June 2002 17:58
Subject: 34: Impacts of GM plants/animals on genetic diversity
This is from Professor Muir. I am a population geneticist who works in both molecular genetic and conventional breeding of poultry and fish, and development of methods to pre-determine environmental risk of GM plants and animals.
My message below is in response to Rajaratnam Muhunthan message 2 (June 3) and others relating to genetic diversity. The statement he made: "The million dollar question is whether gene flow from GM to non-GM populations will affect genetic diversity and pollute its purity?"
There are many different levels of genetic diversity. At the lowest level is
1) genetic variability within species, at the next level is
2) variability among species within a community, at the highest level is
3) variability among communities across geographic region.
GM plants or animals may affect all or none of the above based on the following reasoning.
Level 1. Maintenance of genetic variability within a species is what animal breeders are most concerned about and is vital to long term genetic improvement of domestic species. The same genetic variability is also vital to natural selection for continued improvements in fitness as environments or pathogens change. The impacts will be different for species in nature and those domesticated.
For those in nature, the question is how can a GM plant or animal which escapes into an ecosystem impact within species genetic diversity? A transgene should be thought of as a mega-mutation, and nothing more. Whether it spreads or not in an ecosystem through vertical gene transmission depends on how it impacts all components of fitness, including for example mating success (see Muir, WM and R.D. Howard 2002. Environmental Risk Assessment of Transgenic Fish With Implications for Other Diploid Organisms. Transgenic Research 11:101-114). The following assumes the GM plant or animal can mate with native species, i.e. vertical gene transmission (VGT). Otherwise the GM organism is simply an invasive exotic which will be dealt with at the next level (2) below. However, even if the transgene spreads, the transgene does not necessarily reduce variability at other loci because genetic recombination prevents this loss. This argument assumes the population size is large enough and fitness advantage (if any) of the transgene is small enough such that many generations of selection will occur before fixation of the transgene (this allows for the necessary recombination to occur and linkage disequilibrium to be dissipated).
If the population size into which the transgene spreads (through VGT) is small and the fitness advantage of the transgene is large (such as for viral resistance to a disease that is sweeping an island), then stochastic events will fix the transgene before linkage equilibrium can be established. In this case, genes closely linked to the transgene insertion site will be fixed along with the transgene and some genetic variability will be lost. If the number of chromosomes is large, the loss in genetic variability will be small (because those genes will not be linked to the transgene).
Impacts of a transgene on domesticated species is entirely different, this is because the breeder decides who reproduces, not the plants or animals. In this case, the transgene can have a major impact on loss of genetic diversity. If the GM plant or animals is so desirable (profitable) that one would be forced out of business if not used, the GM organism will replace the majority of all existing lines with tremendous loss of genetic variability. However, this is not unlike what is already occurring with conventional breeding. For example, there are millions of Holstein cows in the world, but the effective population size is less than a few hundred. This is a result of two factors, AI and competition. Everyone wants the highest producing cows, and sperm is readily available and for sale to everyone. This results in relatively few bulls fathering most of the cows. Thus, I really do not see that transgenes create any new threats to genetic variability that we have not already seen with conventional breeding (remember the male sterile corn of a few decades ago? That was non-GM but demonstrates this concern).
Level 2) variability among species within a community. If the transgene allows the species to expand its niche, then competitive exclusion may occur with loss of species from a community and cascading effect on other species and perhaps other communities (level 3 effects).
Level 3) If the GM organism is introduced into multiple communities, and level 2 loss occurs, then homogenation of communities will occur. This is exactly the same result as with introduction of exotic species, and with the same level of concern. Homogenation of species across communities results in lost opportunities for evolution to occur through co-adapted gene complexes, i.e. there will be no local adaptation or exploration of fitness surfaces through random genetic drift.
From all the above, I see the risk of GM plants or animals to level 1) genetic diversity mainly affecting domesticated species, but I do not think that risk is any greater than with domestic breeding, although that risk can be large. In nature, loss of genetic diversity through GM organisms will mainly be level 2 or 3.
William M. Muir, Ph.D.
1151 Lilly Hall
W. Lafayette, IN 47906
bmuir (at) purdue.edu