Yamnaya culture of Bronze Age Europe owed half its ancestry to different gene pool, say scientists discovering "major new piece in human ancestry jigsaw"
Zoologists have used a human right temporal bone from more than 13,000 years ago in a cave in West Georgia to sequence ancient genomes and pinpoint a new “fourth strand” of ancestry in Europeans related to hunter-gatherers from pre-Ice Age Africa.
© Eppie Jones
A Caucasus population settled on the border of southern Russia and Georgia in increasing isolation before the last Glacial Maximum age, when ice sheets stretched furthest, around 25,000 years ago. Sheltering in the mountains, the group only met other populations following a period of thawing, resulting in the genetic mixture which created the Yamnaya culture of herders who swept into western Europe 5,000 years ago.
“The question of where the Yamnaya come from has been something of a mystery up to now,” says Dr Andrea Manica, from the Department of Zoology at the University of Cambridge.
© Eppie Jones
“We knew that the Yamnaya had this big genetic component that we couldn’t place, and we can now see it was this ancient lineage hiding in the Caucasus during the last Ice Age.
“We’ve found that their genetic make-up is a mix of Eastern European hunter-gatherers and a population from this pocket of Caucasus hunter-gatherers who weathered much of the last Ice Age in apparent isolation.
“This Caucasus pocket is the fourth major strand of ancient European ancestry – one that we were unaware of until now.”
Specialising in metallurgy and animal-herding skills, the culture’s ancestral strand is now present in almost all populations from Europe. The Caucasus hunter-gatherer genome showed a continued mixture with the ancestors of the early farmers in the Levant area, ending just before the peak Ice Age, when it shrunk – a sign of breeding between those with increasingly similar DNA.
In a further significant discovery, the sequencing revealed a similar population migrated as far east as South Asia.
“India is a complete mix of Asian and European genetic components,” says Eppie Jones, of Trinity College, who is the first author of the paper.
“The Caucasus hunter-gatherer ancestry is the best match we’ve found for the European genetic component found right across modern Indian populations.”
A separate 10,000-year-old burial in Western Georgia also informed the research.
“The widespread nature of the Caucasus hunter-gatherer ancestry following its long isolation makes sense geographically,” says Professor Ron Pinhasi, a lead senior author from University College Dublin.
“The Caucasus region sits almost at a crossroads of the Eurasian landmass, with arguably the most sensible migration routes both west and east in the vicinity.
“The sequencing of genomes from this key region will have a major impact on the fields of palaeogeneomics and human evolution in Eurasia, as it bridges a major geographic gap in our knowledge.”
David Lordkipanidze, the Director of the Georgian National Museum and a co-author of the paper, said palaeogenetic information from the museum’s extensive fossil collection would add to the conclusions from the first sequencing.
The fourth strand
- Following the ‘out of Africa’ expansion, some hunter-gatherer populations migrated north-west, eventually colonising much of Europe from Spain to Hungary.
- Other populations settled around the eastern Mediterranean and Levant, where they would develop agriculture around 10,000 years ago. These early farmers then expanded into and colonised Europe.
- At the start of the Bronze Age around 5,000 years ago, there was a wave of migration from central Eurasia into Western Europe – the Yamnaya.
- By reading the DNA, the researchers were able to show that the lineage of this fourth Caucasus hunter-gatherer strand diverged from the western hunter-gatherers just after the expansion of anatomically modern humans into Europe from Africa.
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Three prehistoric places to see
Grime's Graves Prehistoric Flint Mine, Norfolk
Grime's Graves is the only Neolithic flint mine open to visitors in Britain. A grassy lunar landscape of over 400 shafts, pits, quarries and spoil dumps, they were first named Grim's Graves - meaning the pagan god Grim's quarries, or 'the Devil's holes' - by the Anglo-Saxons.
Kents Cavern Prehistoric Caves, Torquay
For thousands of years this cave was home to ancient humans, sheltering from extreme weather, making fires, shaping stone tools and hunting wild Ice Age predators. You will be taken back to these ancient times as you walk through the extensive labyrinth of caverns surrounded by spectacular stalactite and stalagmite formations.
Skara Brae Prehistoric Village, Orkney
When a wild storm on Orkney in 1850 exposed the ruins of ancient dwellings, Skara Brae, the best preserved prehistoric village in northern Europe, was discovered. The excavated farming settlement dates back 5000 years.