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worth repeating |
| Joan Roughgarden, professor of
biological sciences at Stanford University, gave this year’s
Andrea Carson Coley Lecture. Some excerpts: “The question then arises of what it is that’s good about sex. . . . . Where sex turns out to be important is in what Wall Street types call ‘portfolio balancing.’ If you look at the gene pool of a species at any one time, you’ll see that the species has lots of different genotypes in it, and at any one time some of those genotypes are doing really well and others aren’t. As a result, some of the progeny of those genotypes wind up increasing through time. . . . Sex redistributes the investment of the species into the different entries in the portfolio. And so just as a diverse portfolio that’s continually being rebalanced will actually outperform a highly concentrated fund, that’s why species that reproduce sexually survive over the long run. “So it’s the responding of a species to a continual changing of the environment where sex becomes very important. . . . The presence of sexual reproduction argues that diversity is absolutely fundamental to a species’ surviving over the long run. If you think about it, sometimes genes could be, so to speak, down on their luck. If you look at a species at any one time, you might say some of the genes are bad genes, because the carriers of those genes are not doing very well at that time, and yet it’s the very shuffling of the gene pool’s investment from one set of genes to another over time which is leading to the long-term survival. . . . The medical model of diversity is to pathologize diversity, and the evolutionary model of diversity is to view it as necessary for species survival over the long term, and not to pay a lot of attention whether at any one time certain genes are down on their luck.” |
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