Race

John Wilkins has a post on race where he expresses skepticism about its biological reality. He comment was in response to a post on my other blog (by another individual), but I'll stand by it. I've talked abut race in the past, and I'm not into the topic at this point since it is going over old ground, but a few quick responses.... Re: Lewontin's point about 85% within group vs. 15% between group variance, that is true, at one locus, but it ignores the correlation structure across loci. This is elucidated by mathematical geneticist Anthony Edwards in his paper from a few years back (PDF here). You can also think of it in terms of intersections of loci or traits. Consider that I have brown skin. If I tell you just that, you can't infer much, there are many populations which have brown skin. If I told you my hair was straight, that would narrow the possibilities some. If I told you I lacked an epicanthic fold, that would narrow the possibilies further. If I told you I was of blood group A that would narrow the possibilities further (this might seem strange to you, but when you note that my complexion overlaps with many indigenous peoples of the New World, but that these populations are overwhelmingly blood type O, with a small minority of A centered around a few tribes in northwest North America, you can use it to exclude some possibilities). Particular traits are correlated together in South Asians, and that shows. The same principle operates with genetic loci. If you want an appeal to authority, here is Richard Dawkins on page 408-409 in The Ancestor's Tale: