Nice Rats, Nasty Rats: Maybe It’s All in the Genes - New York TimesOf course the domestication of humans might have occurred long before homo sapiens, perhaps in homo erectus. Or maybe it's just ongoing. There may be a tension between domestication and sexual selection behaviors; it would be easy to imagine domestication varying over the course of human history ...
...Richard Wrangham, a primatologist at Harvard, has proposed that people are a domesticated form of ape, the domestication having been self-administered as human societies penalized or ostracized individuals who were too aggressive.
Dr. Paabo said that if Mr. Albert identified the genes responsible for domestication in rats, “we would also look at those genes in humans and apes to see if they might be involved in human evolution.”
Human self-domestication, if it occurred, would probably not have exactly the same genetic basis as tameness in animals. But Mr. Albert said that if he could pinpoint the genetic difference between the tame and ferocious rats, he would compare the chimp genome and the human genome to see if they showed a similar difference.
One possibility is that a handful of genes — perhaps even just one — underlie all the changes seen in domestication. A structure in the embryo of all vertebrates, known as the neural crest, is the source of cells that constitute much of the face, skull and pigment cells, and many parts of the peripheral nervous system and endocrine system. If the genes in the neural crest cells were delayed just a little in coming into action, a whole range of tissues could be affected, including the maturation of the adrenal glands that underlies the first fear response of young animals, Dr. Fitch has written.
Could a single gene that affects the timing of neural crest cell development underlie the whole phenomenon of animal and human domestication? “There would be one happy science Ph.D. student if that were true,” Mr. Albert said.
Update 7/26: I didn't give enough thought to the key concept here -- how quickly this transition occurs. Eight generations for the foxes. That's not an eyeblink, it's an instantaneous flip/flop on evolutionary time scales. This wild/tame behavior smells like some kind of evolved "switch mechanism" -- the organism can range from 'viscious' to 'tame' very quickly depending on environmental changes. I think there may even be evidence of this in baboon troupes that have been isolated by rivers and the like. I wonder if this is unique to mammals or if it's seen in birds and other social animals. (Ants, perhaps?)
With this kind of responsiveness isolated groups of humans and pre-humans might have gone back and forth many times over the past million years or so, depending on the local environment. We know the level of violence in medieval times was shocking by today's standards, and we know from gene frequency studies that human evolution can act on surprisingly short time scales. Wouldn't it be interesting if anglo-saxon of 2006 were genetically more domesticated than the anglo-saxon of 1000 ACE?