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November 03, 2004

Salt of the Earth

Dienekes blogged about the latitudinal differences in human populations on the phenotype of salt retention a few weeks ago, but I noticed this good popular summation about this research today, and thought I'd link to it. The skinny is that a polymorphism of a gene implicated in salt retention that is the common to Sub-Saharan Africans gives way as one moves north to a "non-functioning" variant as the dominant type. You can connect the dots as to how that relates to hypertension across various ethnic groups (and dosage guidelines for salt consumption). Here is the abstract in The American Journal of Human Genetics.

As I said in the post below, the data is out there, and there seems to be a progressive accumulation of the reality that there is a great deal of functional variation on many locii in our species driven by natural selection and the release of functional constraints (and often a simultaneous importance of sexual selection). Assuming that the Out-of-Africa hypothesis is correct, it seems we are seeing a pattern of a diversification of the human population as it sweeps out of its African ur-heimat. Whether you think it is trivial or not I leave up to you. On this blog we do push the envelope to the final and ultimate Holy of Holies, specialization of various mental modules in human subpopulations. Yet, I even if you step back from that particular precipice, it is fascinating, and I think relevant from a utilitarian angle (think medicine) that interindividual and intergroup variation manifests itself on many levels of our biology. As long as the atomic facts themselves are accepted whether you think the molecules that can be assembled up from them are trivial or not in scope and relevance is to me rather trivial itself.

Posted by razib at 01:25 AM