This is a response to the post by Doublehelix re: races and human biology emerging out of Daniel Lende’s post on IQ and environment.. The issue of human biological units and intelligence/cognition is very old and seems to keep appearing despite serious problems in the way the positions are most commonly framed. This is a core factor in discussing neuroanthropology. It is extremely important to realize that if you are going to use race as a biological unit then you must define it! I would like to ask Doublehelix to present a definition of human groups that are consistently identifiable by a set of biological characteristics that separates them from other such groups. There is no argument that human populations, both regional and meta-populations, vary in a number of biological characteristics. However, are these evolutionary units or of evolutionary relevance? Are there functional differences across human groups (once you are able to define what you mean by group).
Discovering shared frequencies of alleles in regional and meta-populations is expected via standard models of gene flow. However, globally humans break the standard models of gene flow by their very low inter-population variation relative to species wide variation (not to discount the reality of a lot of variation across the geographical distribution of our species and huge inter-individual variation)…Doublehelix uses the Risch and other articles to refute this, but ignores all of the work by many, many others (see below for a sample) that discuss and explain why one might see clustering of some allelic variation as associated with geography, and what that might or might not mean in an evolutionary sense. We are well beyond Lewontin 1972… Allele frequency clusters are not races or even biological units…the association of function with specific distributions of frequency patterns of various alleles can and should be done, but has to be done with extreme care and we must play by the biological rule book. If you are comparing biological units they must be biologically, not socially, defined.
The statement “As for the notion that race is not supported by biology, I ask: Why do races differ so profoundly in so many different characteristics, such as IQ, lactose tolerance, the resistance to malaria, skin and hair color, the effectiveness of certain drugs?” is rooted in a severe simplification…for example, lactase production is widespread across 100s of human populations with peaks in Northern European, east African and even middle eastern populations…so what does it say about race? Malaria resistance via one of the 5 sickle cell mutations occurs with high frequencies in West Africa, but also South West Asia and the Middle East? What race is that? Hair color ands type are widely distributed…but not markers of unity…for example if having tight curly black hair unified groups then populations in Papua New Guinea and Nigeria would be linked…they are not. As for drug differences, this is a very important and complex area of investigation where we actually see some amazing integration of social, physiological and contextual patterns (see recent BiDil research) but not clear patterning of socially defined races as showing any specific identifiable bio-based markers.