Ancient Human DnaOld human DNA
Old DNA rewrites the story of man (and the Neanderthal)
In 2007, Reich's task was to analyse the DNA for characters that mixed Neanderthals with human beings - an concept he was "deeply suspicious" of at the university. Surprisingly, DNA unveiled that people and Neanderthals mixed in their common European years.
Today, the individuals who carry the most Neanderthals' DNA are not in Europe, but in East Asia - probably because of the pattern of ancient human migrations in Eurasia in the millennia following the extinction of Neanderthals. This all paints a complex but vibrant image of human history. From the beginning of our race, man has been in motion, sometimes replacing and sometimes mixing with the indigenous populations, first with hominid like Neanderthals and later with othermen.
Since then, Reich has transformed his laboratory at Harvard Medical School into a "factory" for old DNA studies. In his new work, Who We Are and How We Got Here, he shows the countless ways in which the studies of ancient DNA bombings are praised in the hall of time. For example, in Europe, ancient DNA identifies migratory phases in the continents where groups of humans have successively or almost completely displaced the indigenous populations.
The work is not uncontroversial, especially since these substitutions are hard to justify. Sarah Zhang: You recently released two works in which you analysed over 600 old European genera. Are you writing in your almanac that you want to "build an American-style genome factory" and "industrialize old DNA"?
How does an old plant of genomes look like? Usually, several persons work in simultaneous operation in a single room to transform bone or tooth into powders. We are always looking for ways to cut cost in each phase so that we can shorten the processing times of a specimen.
Zhang: How much does it take to digest an old DNA specimen now? What makes Cheddar Man look so different from Europeans today? We know a great deal about how migrating in Europe, where we currently have the best information - even if this will be changed in the oncoming years.
41,000 to 39,000 years ago, Neanderthals were superseded by humans in West Europe. We have the first human specimens in Europe that are about 40,000 years old and have no genetic relation at all to today's Europeans. For the first in history you can see for the first to see humans related to later hunters and collectors in Europe who have made a small contribution to today's Europeans.
Then, the shields fall through North Europe and many of these population are hunted into these shelters on the South Peninsula of Europe. There is a repeat of North Europe after the glacial period from the south-west, probably from Spain, and then also from the south-east, probably from Greece and perhaps even from Anatolia, Turkey.
Then again, after 5,000 years, there is this crowd at the beginning of the Bronze Age of the steppes, who probably also speak these tongues, which are today used by the vast majority as well. As for the Cheddar man, he belongs to one of those groups that revived North Europe from the North after the Ice Age.
This group was shaped by the ancestors of the south-eastern Europeans. Not many of the skin-lightening changes that were present in the first peasants and even more so in the later steppic pastorists. You don't have the blonde hairdos that are typical of many North Europeans today.
Zhang: You said that the old DNA has altered the way we see archeology from those times. Archeology has always been politically, especially in Europe. It went so far as to say that when you see the expansion of these pot, you actually see a human expansion, and there is a one-to-one map for these things.
The Nazis later used his idea in publicity to say that a certain group in Europe, the Aryans, spread in all European countries. One of the things the old DNA shows is that the corded commodity civilization is coherent with a group of humans.
Editor's note: The corduroy produced earthenware with cord-like ornaments which, according to old DNA research, originate from the steppes. It was a very delicate subject for some of our co-authors, and one of the co-authors stepped down because he felt that we would return to the archaeological migrations concept that pans are the same as humans.
A number of other co-authors from different parts of mainland Europe share this concern. The results are almost diametrical in contrast to what Kossina thought, because these corduroy goods came from the East, a place that Kossina would have scorned as a well.
However, it is still the case that there are large numbers of displaced persons, and so I think what DNA is doing is enforcing the hands of this archaeological debate and showing that there are indeed large numbers of migrants. Sometimes they are harsh and tragic, and they are large-scale displacements within a relatively brief timeframe.
This is the first we' ve seen. Zhang: I think at one point in your volume you actually describe old DNA scientists as the "barbarians" at the doorstep of historical science. The barbarian cannot speak in an informed and scholarly manner, but they have entrance to arms and ways of looking at things that other human beings have not seen.
In the past we have repeatedly learnt that it is risky to ignore the barbarian. You say that genetic information is now often ahead of archeology, and you can always find these large, tragic populations in the whole of humanity' s past, which cannot yet be fully described. What should we think about this replacement populace?
Are there risks of human interpretation or misinterpretation as a consequence of the supremacy of one group over another? If you see that these Neanderthal substitutes have been substituted by those of the Neanderthal peoples, or Europeans and Africans who have essentially substituted the indigenous peoples of America in the last 500 years, or the Stonehenge-builders, who were obviously extremely ingenious, by these men of the continents, that says nothing about the inherent potentials of these man.
As far as the immunity system is concerned, one of the reasons why desert dwellers have spread so successfully in Europe that they have introduced the bullenpest. This reminds me that many great migration has occurred in the annals of humanity, which replaced earlier population. Of course, contacts between Europe and Africa and the New World have been a major experience for our race over the last 500 years.
However, there have always been far-reaching and earth-shattering incidents, every few thousand years in our story, and that is what the old DNA tells us. However, I think they are very fringe individuals, and there is of course a worry that they could affect the mains.