90% of the Neolithic British Gene Pool Was Replaced by Beaker Immigrants
Scientists once could reconstruct humanity's distant past only from the mute testimony of ancient settlements, bones, and artifacts.
No longer. Now there's a powerful new approach for illuminating the world before the dawn of written history -- reading the actual genetic code of our ancient ancestors. Two papers published in the journal Nature on February 21, 2018, more than double the number of ancient humans whose DNA has been analyzed and published to 1,336 individuals -- up from just 10 in 2014.
The new flood of genetic information represents a "coming of age" for the nascent field of ancient DNA, says lead author David Reich, a Howard Hughes Medical Institute investigator at Harvard Medical School -- and it upends cherished archeological orthodoxy. "When we look at the data, we see surprises again and again and again," says Reich.
‘The Stone Age’ (1882-1885), detail of a painting by Viktor M. Vasnetsov. ( Public Domain) Ancient DNA studies provide surprising information on our prehistoric ancestors.
Together with his lab's previous work and that of other pioneers of ancient DNA, the Big Picture message is that our prehistoric ancestors were not nearly as homebound as once thought. "There was a view that migration is a very rare process in human evolution," Reich explains. Not so, says the ancient DNA. Actually, Reich says, "the orthodoxy -- the assumption that present-day people are directly descended from the people who always lived in that same area -- is wrong almost everywhere."
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Instead, "the view that's emerging -- for which David is an eloquent advocate -- is that human populations are moving and mixing all the time," says John Novembre, a computational biologist at the University of Chicago.
Stonehenge's Builders Largely Vanish
In one of the new papers, Reich and a cast of dozens of collaborators chart the spread of an ancient culture known by its stylized bell-shaped pots, the so-called Bell Beaker phenomenon. This culture first spread between Iberia and central Europe beginning about 4,700 years ago. By analyzing DNA from several hundred samples of human bones, Reich's team shows that only the ideas -- not the people who originated them -- made the move initially. That's because the genes of the Iberian population remain distinct from those of the central Europeans who adopted the characteristic pots and other artifacts.
a, ‘All-Over-Cord’ Beaker from Bathgate, West Lothian, Scotland. Photograph: © National Museums Scotland. b, Beaker-complex grave goods from La Sima III barrow, Soria, Spain . The set includes Beaker pots of the so-called ‘Maritime style’. (Junta de Castilla y León, Archivo Museo Numantino, Alejandro Plaza )
But the story changes when the Bell Beaker culture expanded to Britain after 4,500 years ago. Then, it was brought by migrants who almost completely supplanted the island's existing inhabitants -- the mysterious people who had built Stonehenge -- within a few hundred years. "There was a sudden change in the population of Britain," says Reich. "It was an almost complete replacement."
For archeologists, these and other findings from the study of ancient DNA are "absolutely sort of mind-blowing," says archaeologist Barry Cunliffe, a professor emeritus at the University of Oxford. "They are going to upset people, but that is part of the excitement of it."
Vast Migration from the Steppe
Consider the unexpected movement of people who originally lived on the steppes of Central Asia, north of the Black and Caspian seas. About 5,300 years ago, the local hunter-gatherer cultures were replaced in many places by nomadic herders, dubbed the Yamnaya, who were able to expand rapidly by exploiting horses and the new invention of the cart, and who left behind big, rich burial sites.
Archeologists have long known that some of the technologies used by the Yamnaya later spread to Europe. But the startling revelation from the ancient DNA was that the people moved, too -- all the way to the Atlantic coast of Europe in the west to Mongolia in the east and India in the south. This vast migration helps explain the spread of Indo-European languages. And it significantly replaced the local hunter-gatherer genes across Europe with the indelible stamp of steppe DNA, as happened in Britain with the migration of the Bell Beaker people to the island.
The grave of a 16–18 year-old female and a 17–20 year-old male dating to c.2000-1950 BC. Both are buried with a fineware beaker. ( Dave Webb, Cambridge Archaeological Unit )