Oldest Human Genomes Reveal How a Small Group Burst Out of Africa
The New York Times
DNA from European fossils dating back 45,000 years offers new clues to how our species spread across the world.
Some 45,000 years ago, a tiny group of people — fewer than 1,000, all told — wandered the icy northern fringes of Europe. Across thousands of miles of tundra, they hunted woolly rhinoceros and other big game. Their skin was most likely dark. To keep warm in the bone-chilling temperatures, they probably wore the hides and furs of the animals they killed.
These hardy people of the Ice Age, known as the LRJ culture, left behind distinctive stone tools and their own remains in caves scattered across Europe. On Thursday, researchers revealed the genomes of seven LRJ individuals from fossilized bones found in Germany and the Czech Republic — the oldest genetic specimens of modern humans yet found.
It turns out the LRJ people were part of the early human expansion from Africa to other parts of the world. But theirs was a surprisingly recent migration.
The common ancestors of the LRJ people and today’s non-Africans lived about 47,000 years ago. In contrast, studies of remains in Australia suggest that modern humans reached that continent 65,000 years ago. And in China, researchers have found what look like the bones of modern humans dating back 100,000 years.
The huge gap between those ages could change our understanding about how humans spread across the world. If the ancestors of today’s non-Africans didn’t sweep across other continents until 47,000 years ago, then those older sites must have been occupied by earlier waves of humans who died off without passing down their DNA to the people now living in places like China and Australia.
“They cannot be part of the genetic diversity that’s present outside Africa,” said Johannes Krause, a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and an author of the new study.
