Genetics uncover Europe’s fourth ancestral tribe

Geneticists have detected a fourth ancestral "tribe" which contributed to the modern European gene pool.

Research shows Europeans are a mixture of three major ancestral populations - indigenous hunters, Middle Eastern farmers and a population that arrived from the east in the Bronze Age.

DNA from ancient remains in the Caucasus has now revealed a fourth population that fed into the mix.
Scientific advances in recent years have allowed researchers to retrieve and analyse genomes from ancient burials. The genome is the genetic blueprint for a human, contained within the nucleus of every cell.

This deluge of data has transformed our understanding of the modern human genetic landscape. It has also shown that present-day genetic patterns are poor guides to ancient ones.

The first layer of European ancestry, the indigenous hunter-gatherers, entered Europe before the Ice Age 40,000 years ago. But 7,000 years ago, they were swept up in a migration of people from the Middle East, who introduced farming to Europe.

About 5,000 years ago, herders called the Yamnaya entered Europe from the eastern Steppe region - in present day Ukraine and Russia.

These horse riding metal workers may have brought Indo-European languages with them; today this language family comprises most of the tongues spoken in Europe. The discovery of plague DNA in Yamnaya burials and a population decline in Europe around the same time has led some researchers to wonder if their passage west was facilitated by the spread of disease.
northern and central Europe

The Yamnaya transformed the gene pools of northern and central Europe, such that some populations, like Norwegians, owe around 50% of their ancestry to these Steppe pastoralists.

But the Yamnaya were themselves a mixed population. Around half of their ancestry came from a sister group to the hunter-gatherers who inhabited Europe before farming, while the other half appears to be from a population related to - but noticeably different from - the Middle Eastern migrants who introduced farming.

Researchers have now analyzed genomes from two hunter-gatherers from Georgia that are 13,300 and 9,700 years old. The results show that these Caucasus hunters were probably the source of the farmer-like DNA in the Yamnaya.