RSS
Ancient DNA has made it big time, with a write up in The New York Times by Carl Zimmer, From Ancient DNA, a Clearer Picture of Europeans Today. The primary sources of the piece are two papers published recently in Europe, Ancient human genomes suggest three ancestral populations for present-day Europeans (ungated version) and Genome flux and stasis in a five millennium transect of European prehistory. Like the earlier mtDNA work on ancient DNA what these results are suggesting is that European demographic history has been punctuated by periodic discontinuities. Here’s an important bit from the Zimmer article:
Archaeologists have found that early farming culture didn’t change drastically for the next 3,700 years. But about 4,000 years ago, the Bronze Age arrived. People started using bronze tools, trading over longer networks and moving into fortified towns.
Dr. Pinhasi and his colleagues found that the era also brought a sudden shift in human DNA. A new population arrived on the Great Hungarian Plain, and Dr. Reich believes he knows who they were: the northern Eurasians.
It seems really unlikely that Europeans are special in this tendency, with broad world-wide trends as outlined in Towards a new history and geography of human genes informed by ancient DNA. For decades there have been books written about the coming for the Indo-Europeans. David Anthony’s The Horse, the Wheel, and Language is probably the best recent summation of the “they came out of the steppes” viewpoint. If there is a major update on this it now looks like the demographic impact of the Indo-Europeans was much greater than we had previous imagined. But are Indo-Europeans special? Probably not…earlier work suggested major discontinuities in Europe with the arrival of agriculture. Later in Africa you had the Bantu expansion, which replaced most of the local people. And as John Hawks points out the ancient Siberian who lived ~45,000 years ago probably comes from a group with no modern descendants. With the disappearance of the Ma’lta boy’s people ~20,000 years later from eastern Siberia it suggests that the heart of Eurasia has been roiled multiple times since the arrival of anatomically modern humans.
Addendum: I would take minor issue with the title of The New York Times piece. The picture isn’t really clearer, but cloudier. It’s just that the old clear picture was wrong, and the new cloudy picture is less wrong. Ultimately the clouds may clear, but we need more samples for that.
As I said in Ancestral Journeys (2013).
Nice piece Razib.
http://www.unz.com/gnxp/men-of-bronze-men-of-iron/#comment-753668
What the New York Times left out of the story is the fact that the newspaper itself has for years been pushing the Neolithic-Anatolian theory of Indo-European origins and spread, which is of course directly contradicted by this study, and by virtually all other lines of empirical evidence as well. Two years ago, a major article in the Times by Nicholas Wade claimed that a new phylogenetic-phylogeographical study of Indo-European languages published in Science essentially proved that the language family originated among Neolithic farmers in what is now Turkey. The study in question, however, was based on two nonsensical postulates: a. that languages diffuse across the landscape like virus, and b. that cognates (words derived from a common ancestor) can be treated like genes in order to establish linguistic relationships through phylogenetic analysis. The study also ruled out migration ahead of time, allowing demic diffusion as the only possible mode of population expansion. No reason was provided for the latter assumption, but one can read between the lines: because that’s what Colin Renfrew and his fellow processual archeologists decreed.
http://www.unz.com/gnxp/men-of-bronze-men-of-iron/#comment-756047
I would love to hear more about the brilliant series of papers written by the Reich team at Harvard which includes Patterson and Lazaridis. These papers are hidden behind a pay wall and quite honestly, I wouldn’t understand them very well even if they weren’t. It is hardly an overstatement to say this group of brilliant geneticists are rewriting human prehistory or at least scientifically confirming what was previously only suspected. If a specialist such as Razib would explain the particulars of how these scientists take this raw data and turn it into proofs I think it would be appreciated by many. It is in my opinion an under reported scientific news story that began with the discovery that we are part Neanderthal is continuing with amazing papers like the one mentioned above that discovered three ancestral populations for modern day Europeans.
http://www.unz.com/gnxp/men-of-bronze-men-of-iron/#comment-756506