Hi, I am Wayne Parrott. I have degrees in Agronomy followed by Plant Breeding and Genetics. I have 25 years of working on transgenics at the University of Georgia. The past few years I have been spending ever greater food/feed safety assessment and environmental risk analysis (ERA), most recently having finished an ERA guide tailored for Latin America. I want to begin by thanking the sponsors of this forum for the opportunity, and the moderator for making it happen. I have belatedly been going through the postings, and have some comments I would like to make. Although several products have been mentioned as being in the pipeline and potentially available in the past 5 years, regulatory issues will prevent most from leaving the lab. A key topic is gene flow, as illustrated in messages 33, 44, 51, 60 and others on Bt brinjal. The gene flow discussions require some science and objectivity if we are to move forward, not just for brinjal, but other crops that could be useful for developing countries. Whether or not the crop will cross with its wild or feral relative is really the wrong question, as gene flow is far more complex than just crossing. I just start on the premise that crosses will occur. Thus the relevant question is about the consequences of such crosses. First it is necessary to remember that transgenes do not flow by themselves-- it is chromosomal segments that flow, not isolated genes. The transgenes are linked to other genes on a chromosome, and the alleles of these genes on the chromosome tend to be for agricultural adaptation. Secondly, it is necessary to distinguish between pollen flow and gene flow. Technically, gene flow has not taken place unless the gene is present in advanced generations (what breeders call introgression). Introgression tends to occur if there is continued pressure from pollen flow, or if the transgene confers an advantage in the wild. For the latter it is important to note --particularly for Bt-- that the pests that limit a crop under agricultural conditions usually are not the same ones that limit the growth of their relatives in the wild. In addition, any advantage given by the transgene can be counteracted by the other genes/alleles on the chromosomal segment that is flowing (a version of what breeders call 'linkage drag'). Everything needs a point of reference to use as a basis for risk assessment. First, is there anything about the transgene that can increase the ability to participate in crosses, and 2), in what way are the *consequences* of gene flow from a transgenic crop different from the consequences of gene flow from a conventional crop? Mention is made in message 60 that the cross of conventional brinjal with S. violaceum leads to the production of vigorous hybrids. What is the fate of these? Have they led to new weed problems? Invasiveness? Any adverse effect? If not, what is it about crossing with transgenic brinjal rather than regular brinjal that can make a difference in the behavior of the hybrids? Most likely, the answer is nothing; regardless, it is an easy test to conduct. In the end, even if we assume that introgression does occur, "destruction of biodiversity" is by no means an automatic result. After all, all sorts of cultivated and wild solanums have coexisted for millennia without destroying each other, despite any genes that may have flowed from crops into wild and feral relatives. Again, it boils down to whether the transgene would present different issues from the gene flow that has taken place in the past, and thus have detrimental consequences. The answer is specific to each gene-crop combination, so a case by case evaluation is still needed to determine if gene flow could be detrimental. In the event of gene flow, it is important to emphasize that an extra gene in a genome in no way destroys the identity of that species. Once upon a time we thought that all members of the same species had the same genes in the same order. Perhaps one of the most surprising thing we have learned from all the genome sequencing going on is that the original premise was wrong. Two individuals from the same species can differ by as few as 1 or 2 genes or as many as a couple thousand genes, which keep assorting into different combinations as individuals in the species cross and segregate out. Clearly, species tolerate presence/absence of genes and copy number variation of genes far better than we give them credit for. So, if gene flow from conventionally bred crops has not destroyed biodiversity, what makes gene flow from a transgenic any different? The answer to that question is what risk analysis is all about. Furthermore, any possible damage must be associated to a biologically possible hypothesis, and based on the weight of the evidence where ever possible, and not on single publications. Wayne Parrott Department of Crop and Soil Sciences, University of Georgia, Athens, GA 30602 United States wparrott (at) uga.edu ######################################################################## To unsubscribe from the Biotech-Room2-L list, click the following link: https://listserv.fao.org/cgi-bin/wa?SUBED1=Biotech-Room2-L&A=1