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Archive for October, 2014

Plaque Commemorating the Founding of Harvard College, Cambridge, Massachusetts

Plaque Commemorating the Founding of Harvard College, Cambridge, Massachusetts

I’m still working on the follow-up to my DNA post, but in the meantime I’ve seen a few new reports of interesting research in other parts of the world using techniques similar to what I was talking about. This will provide some context for the Southwest-specific research I’ll discuss later, which is still at a much more rudimentary level that hasn’t yet produced such striking results.

First, commenter ohwilleke, in addition to leaving a long and informative comment about analytical techniques and the usefulness of full-genome sequencing as opposed to mitochondrial studies, points to a recent study of modern inhabitants of Rapanui (Easter Island) that shows clear evidence of prehistoric genetic mixture with people from South America. There have long been theories that there was contact between these populations, but this appears to confirm them with the most solid evidence yet, and provides another glimpse of the complexity of human history. (I’ll address the issue of full genomic sequencing, which has not yet been used on any ancient remains from the Southwest to my knowledge, in the follow-up post.)

Second, there have apparently been two new articles (only one of which I could find, since the news story doesn’t even give the title of the journal the other one was published in) using aDNA techniques on ancient remains from Europe. One study, by a large team including David Reich of Harvard Medical School, found three major sources of ancestry for ancient Europeans: early hunter-gatherers, presumably of African origin; early farmers of Near Eastern origin (which seems to strongly support theories that the spread of agriculture across Europe had migration of people as an important component) who apparently interbred with the hunter-gatherer population to some extent; and a previously unknown group with links to Central Asia and possibly associated with the introduction of Bronze Age material culture. The second study, which looked at remains from later dates than the first, appears to have also found a fourth group that entered eastern Europe during the Iron Age.

Finally, reaching back to a much earlier date, a bone found in a riverbank in Siberia yielded the oldest human genome sequenced to date. Radiocarbon-dated to between 43,000 and 47,000 years ago, the genome is particularly noteworthy because it contains a higher proportion of segments of Neanderthal origin than modern human genomes, which apparently has important implications for theories about the initial peopling of the world by modern humans.

Now, I don’t have access to any of these papers so I haven’t read any of them myself. My comments about them are based on the abstracts and the coverage they’ve gotten in the media, which is of course notoriously unreliable when it comes to highly technical subjects. Still, this should give a sense of the kinds of topics DNA studies are weighing in on. As I said before, DNA research in the Southwest is still at a much more rudimentary level, so don’t expect to see this kind of thing any time soon. It is developing, though, and has great potential to answer important questions of archaeological interest. I’ll explain more about the work that has been done in the next post.

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