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[SANET-MG] comment on transgenes in mexican maize



September 6, 2005

Prof. Joe Cummins

“A comment on “Transgenes in Mexican maize: Desirability or inevitability”

The article “Transgenes in Mexican maize: Desirability or inevitability”

by Peter Raven of the Missouri Botanical Gardens appeared in today’s Proceedings of the National academy of Sciences early addition. Raven is an advocate for genetically modified (GM) crops and for the Monsdanto Corporation. The article contains the comment "Whether or not transgenes are present in landraces in Oaxaca at

present, they will inevitably be found in them as time passes, because of the

nature of the indigenous agriculture I have just described. There they will

persist if they confer a selective advantage on the plants in which they occur,

or they may disappear if they do not confer such an advantage in the prevailing

conditions. Such genes are no more ‘‘invaders’’ into the populations

concerned than any other genes, and the avoidance of such value-laden

terms would presumably assist in the objective conduct of scientific discourse

about the situation. Similarly,the principles of population genetics

certainly do not indicate that they would ‘‘disrupt’’ the germplasm of the

maize populations they might enter"

It is worth pointing out that Raven’s view of population genetics seems unconventional. My understanding of population genetics is that once a gene is fixed in a population , as in the case of the transgenes in maize landraces, in the absence of selection the gene reaches the stable Hardy-Wienberg equilibrium. Only if the gene is deleterious to maize will it disappear from the population. The view that genes reach equilibrium in the absence of selection is consistent with the principles of population genetic while the principles of population genetics don’t seem to make statements about genome disruption. However, the loss of a gene fixed in a population certainly implies that the transgene must have done something wrong to the maize.

Reference

Peter H. Raven Transgenes in Mexican maize: Desirability or inevitability? Perspective Proc. Natl. Acad. Sci. USA, 10.1073/pnas.0506082102 Published online before print September 6, 2005

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