Tuesday, January 1, 2013
At least 7% of the human genome has changed over the past 40,000 years, with most of the change being squeezed into the last 10,000
In fact, human genetic evolution sped up by over a hundred-fold about 10,000 years ago. By then, however, humans had spread over the earth’s entire surface from the equator to the Arctic Circle. They weren’t adapting to new physical environments. They were adapting to new cultural and behavioral environments. They were adapting to differences in diet, in mating systems, in family and communal structure, in notions of morality, in forms of language, in systems of writing, in modes of subsistence, in means of production, in networks of exchange, and so on. This genetic evolution involved changes to digestion, metabolism, and … mental processing. Another fact. By 10,000 years ago, modern humans were no longer a small founder group. They were already splitting up into different geographic populations. So the acceleration of human genetic evolution did not affect all humans the same way. Yes, we are different, and the differences aren’t skin deep.