Oldest British DNA Shows Massive Immigration Since Last Ice Age

Genetic material recovered from two caves suggests that climate change has affected new cultures and lifestyles.

This is the story of two ancient British caves: in Cheddar Gorge, near Bristol, England, about 15,000 years ago, reindeer hunters carved designs on human bones and drank from carved human skulls. A few hundred kilometers to the north, people who lived only a few hundred years later lived on freshwater fish and marine animals, storing their dead in a cave adorned with horse bones and bear teeth pendants.

Archaeologists have long believed that these cultural shifts reflect people’s emergence of new tools and beliefs after the last ice age 18,000 years ago. But new evidence from the oldest known DNA from the British Isles shows that the two groups of cave dwellers had very different origins. These rapid cultural changes were not a sign of the adaptation of Britain’s first postglacial people – they were a sign of completely new people.

“In a short amount of time, you can see a complete population replacement in the British Isles,” says Cosimo Post, a geneticist at the University of Tübingen.

Both caves date back to the Paleolithic, the turbulent time that followed the end of the last ice age. As the climate warmed, open tundra quickly gave way to dense forests. The melting of the ice sheets opened up new areas for human habitation, including what is today Great Britain, which was then connected by a land bridge to mainland Europe.

A genetic analysis of two English caves, published today in the journal Nature Ecology & Evolution, suggests that as the landscape changed, so did populations. New groups of people brought with them new cultural practices, diets, and hunting strategies, replacing or displacing previous populations.

Around 18,000 years ago, global temperatures began to rise. The thick ice sheets that covered two-thirds of Europe for millennia have receded. Groups of people adapted to hunting reindeer and other large mammals pursued their prey north and west into the newly opened frontiers.

Known as the Madeleines, these first postglacial pioneers appear to be genetically similar across Europe – and match perfectly with DNA obtained from a 15,000-year-old bone found in Gough’s Cave in what is now southwest England. Chemical signatures of the bones in Gough’s Cave confirmed that people there ate a Madeleine-style menu of mostly large mammals such as horses and reindeer. They may have nibbled on human flesh from time to time: carved human bones and carefully crafted skullcap cups suggest that ritual cannibalism was part of their culture.

Changes in vegetation and climate displaced the herds of reindeer and other large mammals on which the people of Magdalene relied. Genetic evidence suggests that the Madeleines also disappeared. The DNA extracted from the molar found in Kendrick’s Cave is nothing like the DNA from the people in Gough’s Cave. Instead, it is a match with populations further south in Europe, reflecting the ancestry that geneticists call western hunter-gatherers.

The new people brought new customs with them: the human bones in Kendrick’s Cave indicate that the diet was rich in fish and other sea creatures. And they are buried with no signs of posthumous modification or cannibalism. “They have very different diets, and it looks like it fits in with genetics,” Stevens says. “People seem to move with their habitat.”