Modern Europeans are the descendants of at least three groups of ancient humans, not two as was previously thought, reveals a comparative analysis of DNA from more than 2,300 modern-day humans and nine ancient farmers and hunter-gatherers who lived in Germany, Luxembourg and Sweden, around 7,000 to 8,000 years ago.
A Sami indigenous northern European family in Norway around 1900. The picture was probably taken in 1896 around the Kanstadfjord near Lødingen, Nordland. The adults on the left are Ingrid (born Sarri) and her husband Nils Andersen Inga. In front of the parents are Berit and Ole Nilsen. The lady on the right is Ellen, sister of Ingrid. In front of Ellen are the children Inger Anna and Tomas. The children of Inger Anna are reindeer herders still today. Detroit Publishing Co. print no. 7123.
“There are at least three major, highly differentiated populations that have contributed substantial amounts of ancestry to almost everybody that has European ancestry today,” said Dr David Reich of Harvard Medical School, who is one of the two senior authors of the study published in the journal Nature.
Those include early farmers who brought agriculture to Europe from the Near East, hunter-gatherers from western Europe, and a newly identified group of ancient North Eurasians who arrived in Europe sometime after the introduction of agriculture. That means there were major movements of people into Europe later than previously thought.
To probe the ongoing mystery of Europeans’ heritage and their relationships to the rest of the world, Dr Reich and his colleagues sequenced the complete genomes from the remains of a 7,000-year-old farmer from Germany and eight hunter-gatherers who lived in Luxembourg and Sweden about 8,000 years ago.
They then compared the genomes of ancient people to those of the 2,345 people in their contemporary populations.
“What we find is unambiguous evidence that people in Europe today have all three of these ancestries: early European farmers who brought agriculture to Europe, the indigenous hunter-gatherers who were in Europe prior to 8,000 years ago, and these ancient North Eurasians,” Dr Reich explained.
Further analyses showed that describing present-day Europeans as a mixture of the three populations is a good fit for most, although not all, populations.
The scientists also discovered that ancient Near Eastern farmers and their European descendants can trace much of their ancestry to a previously unknown, even older lineage called the Basal Eurasians.
Basal Eurasians were the first people to separate from the larger group of non-Africans, before other non-African groups diversified.
“This deep lineage of non-African ancestry branched off before all the other non-Africans branched off from one another. Before Australian Aborigines and New Guineans and South Indians and Native Americans and other indigenous hunter-gatherers split, they split from Basal Eurasians. This reconciled some contradictory pieces of information for us,” Dr Reich said.
Next, the researchers plan to figure out when the ancient North Eurasians arrived in Europe and to find ancient DNA from the Basal Eurasians.
“We are only starting to understand the complex genetic relationship of our ancestors. Only more genetic data from ancient human remains will allow us to disentangle our prehistoric past,” concluded co-senior author Prof Johannes Krause of the University of Tübingen, Germany.
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Iosif Lazaridis et al. 2014. Ancient human genomes suggest three ancestral populations for present-day Europeans. Nature 513, 409–413; doi: 10.1038/nature13673
