Book of the week
Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past
The first draft of the true history of humanity has just been written and “it is thrilling in its clarity and scope,” said Peter Forbes in TheGuardian.com. Geneticist David Reich is a leader in the study of ancient DNA, and his new book synthesizes the findings with which he and others in the field have been upending prior conventional wisdom. Reich’s lab at Harvard Medical School was the source of the 2010 finding that all non-Africans have Neanderthal DNA in their genome, the first in a flurry of findings indicating that humans of about 50,000 years ago shared the planet and interbred with various other hominins. Further, our ancestors did not simply migrate out of Africa in a triumphant, ever-expanding tide. Instead, populations shifted one way, then the other, erasing almost every modern claim, outside of Africa, of a tie to a territory’s original settlers.
“Reality, it turns out, is more complex and interesting than scientists ever imagined,” said Razib Khan in NationalReview.com. After explaining how geneticists learned in just the past decade to isolate and decode DNA in ancient human or hominin remains, Reich discusses what this new Rosetta stone has revealed. Consider Europe, which at the end of the last ice age was dominated by dark-skinned, blue-eyed hunter-gatherers who were then displaced about 10,000 years ago by migrant farmers from the Middle East, who also spread south into the Asian subcontinent. Some 5,000 years later, another wave arrived from the Russian steppe, linking Europeans genetically to Native Americans. In short, “we should stop obsessing with our individual ancestries,” said Bryan Appleyard in The Sunday Times (U.K.) “All humans are a hopeless genetic stew.”
But Reich does speak about race, and in a way that indicates his grasp of the concept is “seriously flawed,” said 67 scholars who signed an open letter published by BuzzFeed.com. Though Reich declares race a social construct, he insists on the need to recognize “nontrivial” differences in the genetic makeup of populations that happen to have been labeled as races. We don’t deny his point that geographically based genetic variation exists, or that some populations carry genetic variations that, for example, make members more prone to contracting a particular ailment. But “race” is not the right word for such groups even as shorthand. Listen more closely to Reich, then, because he would agree, said Turi King in Nature. He’s saying we need a less fraught way of talking about group differences, and his book “goes some way to starting that conversation.” ■