What better time than the 200th anniversary of Darwin's birth to speculate about the evolution of yeast? For almost a decade, a debate has alternately aged and simmered, in the wine world and more broadly, about the pros and cons of genetic engineering, especially when applied to things people put in their mouths. By now, the warring sides are pretty well fossilized: You're likely to be for it or agin' it. One position says the technology holds incredible promise, an unprecedented capacity to confront vineyard diseases and make wines in a whole new way, and in any case, breeding has been part of agriculture forever. The other team draws a sharp line between classical breeding and GMOs (genetically modified organisms): Nature never tried inserting a flounder gene in a tomato to help shelf life, as one now-defunct vegetable producer once attempted. Down that road, critics assert, lie Frankenfoods and Frankenwines.