A great surprise that emerges from the genome revolution is that in the relatively recent past, human populations were just as different from each other as they are today, but that the fault lines across populations were almost unrecognizably different from today. DNA extracted from remains of people who lived, say, ten thousand years ago shows that the structure of human populations at that time was qualitatively different. Present-day populations are blends of past populations, which were blends themselves. The African American and Latino populations of the Americas are only the latest in a
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