Genetic analysis of more than 300 bodies buried thousands of years ago has revealed greater and more frequent migrations than had been recognized. The findings could tell us something about what caused ancient people to undertake hard and dangerous journeys. They also show that, for much of the world, there never was a long-gone period of racial purity. The findings further discredit claims about racial differences in intelligence that are currently gaining a renewed, thoroughly undeserved, bout of prominence.
Until recently, assessments of the origins of long-buried bodies depended on clues such as items interred with them. However, as Dr Eran Elhaik of the University of Sheffield noted, this is unreliable. A work of art indicative of a distant culture might have been brought along by migrating people, but could also have been traded or copied across great distances.
Elhaik analyzed DNA instead, using a tool known as ancient Geographic Population Structure (aGPS). "We discovered that Central Europeans were always on the move, continuously mixing with other populations and forming ancient cities in Germany, Denmark, and Hungary, for example, close to modern-day Hamburg and Berlin, and Budapest,” Elhaik said in a statement. “In contrast, Near Eastern peoples tended to stay close to home."
Some of the aGPS findings confirm previous theories, such as a series of great migrations from the Caucasus region to Central Europe between 5,500 and 4,300 years ago.
The work may also shed light on some migrations' causes. "For example, we can identify areas where the land became exhausted from over-farming, and thus caused the movement of populations. We can also pinpoint the formation of city states and 'biodiversity centres', corresponding to ancient empires that drew immigrants from other countries," Elhaik said. In an era where most movement was on foot, and many settled people never traveled more than a day's walk from their place of birth, such journeys were not undertaken lightly.
Like the ancient migrations he is studying, Elhaik's work is harder to conduct than it sounds. "Imagine working with a very short DNA sequences with more holes than bases – not only can we not align this with other ancient sequences, but we also do not know where it is from,” he said, prior to presenting his work at the European Society of Human Genetics conference held in Copenhagen on Monday.
The work demonstrates that, at least for Europe and Asia, there was never a time when most regions were ethnically homogenous. A few isolated areas probably represented exceptions, but most of the world has always had considerable genetic mixing, making it even more unlikely that highly complex traits like intelligence could be correlated racially, despite pseudo-scientific efforts to promote this claim.