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March 11, 2005

Humans greedy for pig?

Pigs domesticated 'many times', at least, that is the inference based on mitochondrial DNA, passed from sow to sow. This point is important because the research seems to be offering up a dichotomy, imported pigs vs. idea diffusion, ergo, domestication of local pigs, but, what about admixture? Imagine that you have a small alien domestic pig population, which over the generations interbreeds with the local pigs. There will be phenotypic variance among the half-breed pigs, but repeated selection for the more "domestic" hybrids could result in perpetuation of the ancestral imported pig phenotype despite the influx (and eventual preponderance) of indigenous DNA on other loci where selection is not operating. To test this hypothesis I guess they would have to try to figure out the coalescence on the "piggy" loci in question, if you get a result where non-Middle Eastern and Chinese pigs are simply branches of the Middle Eastern and Chinese family trees,1 then perhaps those alleles radiated from a few domestication hearths. If the braches reach far back in pig genetic history for all the loci and Middle Eastern or Chinese branches are particularly diverse or old, then I think you can make a strong case for selection of traits of local pigs without much admixture or introduction of alien swine.

Related: "Racial Diversity" and The origins of phenotypic variation?.

1 - By analogy to our species, according to mtDNA non-Africans are simply subsets of the African family tree.

Posted by razib at 01:05 PM