Ancient DNA Is Rewriting Human (and Neanderthal) History

Geneticist David Reich used to study the living, but now he studies the dead.

The precipitating event came in the form of 40,000-year-old Neanderthal bones found in a Croatian cave. So well-preserved were the bones that they yielded enough DNA for sequencing, and it became Reich’s job in 2007 to analyze the DNA for signs that Neanderthals interbred with humans—a idea he was “deeply suspicious” of at the time.

To his surprise, the DNA revealed that humans and Neanderthals did interbreed in their time together in Europe. Possibly even more than once. Today, surprisingly, the people carrying the most Neanderthal DNA are not in Europe but in East Asia—likely due to the patterns of ancient human migration in Eurasia in the thousands of years after Neanderthals died out. All this painted a complicated but dynamic picture of human prehistory. Since the very beginning of our species, humans have been on the move; at times they replaced and at other times they mixed with the local population, first hominids like Neanderthals and later other humans.

Reich has since converted his lab at Harvard Medical School into a “factory” for studying ancient DNA. His new book, Who We Are and How We Got Here, charts the myriad ways the study of ancient DNA is lobbing bombs into the halls of established wisdom. In Europe, for example, ancient DNA is identifying waves of migrations into the continent, in which groups of people serially replaced, or nearly replaced, the local population.

This work is not without controversy, especially as these replacements can be difficult to explain. Reich once had German collaborators drop out of a study when the initial findings seemed to mirror too closely Nazi propaganda about the Aryan race. We discuss this and other aspects of his work below. Our conversation has been condensed and edited for clarity.

Sarah Zhang: You recently published two papers in which you analyzed over 600 genomes from ancient Europeans. In your book, you write you wanted to “build an American-style genomes factory” and “make ancient DNA industrial”? What does an ancient genome factory look like?

David Reich: What we do in our laboratory is we’ve really focused on trying to make data production efficient. We usually have several people working in parallel in a clean room on turning bones or teeth into powder. The powders are dissolved in a watery solution …read more

Source:: The Atlantic – Science

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