Researchers have analyzed DNA from the shin bone of a European male known as Kostenki 14. One of the oldest anatomically modern human fossils on record, he was alive and kicking sometime between 36,200 and 38,700 years ago in western Russia. The findings, published in Science this week, suggest that the European genomic structure also dates back at least 36,000 years.
Today’s Europeans carry a mix of genes from three separate, ancient sources spanning across Asia, the Middle East, and the European landmass. Without knowing how much the earliest Eurasians contributed to the modern gene pool, the origin of Europeans remains up for debate.
So, a large international team led by Andaine Seguin-Orlando from the University of Copenhagen sequenced the ancient genome of Kostenki 14 (pictured above and below) using 13 DNA extractions from his left tibia. They found that his DNA was similar to that of the 24,000-year-old Mal’ta boy found in central Siberia, European hunter-gatherers from the Mesolithic, as well as contemporary western Siberians and many Europeans—but not to that of eastern Asians. That means that western Eurasians and East Asians had already split from each other more than 36,200 years ago.
Kostenki 14 also shared many gene variants with European Neolithic farmers and contemporary people from the Middle East. This suggests that his genome had been influenced by an ancient Eurasian lineage—a mega-population that at times stretched from Europe to central Asia—which laid the foundation for the modern European genome. All of these data indicate that genetic contributions of the earliest Eurasians to modern European populations arrived through gene flow in various directions—and not through a few distinct westward migration events.
Furthermore, the earliest European genetic ancestry survived the peak of the last ice age, and Europe was colonized over the course of 30,000 years. As ice sheets came and went (at one point covering two-thirds of Europe), old cultures died, new ones emerged, and hunter-gatherer populations ebbed and flowed. "But we now know that no new sets of genes are coming in: These changes in survival and cultural kit are overlaid on the same biological background,” Marta Mirazón Lahr of Cambridge says in a university statement. "It is only when famers from the Near East arrived about 8,000 years ago that the structure of the European population changed significantly."
And finally, Kostenki's genome harbored about one percent more Neanderthal DNA than modern humans. And the genetic fragments inherited from his Neanderthal ancestor are larger, "not yet broken by the thousands of natural recombination events that have occurred since,” Rasmus Nielsen from the University of California at Berkeley explains in a news release. “This allowed us to estimate the time of human-Neanderthal admixture to 54,000 years ago.” That part at least fits with the 45,000-year-old Ust'-Ishim genome—the oldest human genome on record—which was published in Nature a couple weeks ago. According to that study, Neanderthal mixing occurred between 50,000 and 60,000 years ago.
Images: Peter the Great Museum (top), Philip Nigst, University of Cambridge (middle)