Human remains from Kendrick’s Cave, from which DNA was recently extracted.

Researchers investigating ancient remains found in England and Wales have determined that they contain some of the oldest human DNA ever obtained in the United Kingdom. The DNA indicates Britain was occupied by two unrelated groups, which the scientists believe migrated to the island at the end of the last ice age.

“Finding the two ancestries so close in time in Britain, only a millennium or so apart, is adding to the emerging picture of [Paleolithic] Europe, which is one of a changing and dynamic population,” said Mateja Hajdinjak, a geneticist specializing in ancient DNA at the Francis Crick Institute, in a University College London release. The research is published today in Nature Ecology & Evolution.

The team looked at DNA from the remains of two individuals, found in caves in England and Wales. The English remains date to about 15,000 years ago, while the Welsh remains date to about 13,500 years ago. The older remains were found in Gough’s Cave, Somerset, and the more recent remains were found in Wales’ Kendrick’s Cave.

When these people were alive, Britain was attached to continental Europe by a now-submerged land bridge called Doggerland. As the climate warmed and glaciers thawed, the sea level rose, cutting off the island.

Both remains are from the late Pleistocene, the epoch characterized by Neanderthals and wooly mammoths and ended with the conclusion of the most recent ice age about 12,000 years ago.

Sequencing the DNA and comparing it to previously analyzed DNA from West Eurasia and North Africa revealed the individuals’ histories. The ancestors of the Gough’s Cave individual arrived from northwestern Europe in a migration about 16,000 years ago, while the Kendrick’s Cave individual appeared to have descended from a western hunter-gatherer group that arrived in Britain about 14,000 years ago, with origins in the near East.

An ancient facial fragment from Gough’s Cave in Somerset.

Besides sequencing the DNA of two people, the researchers also conducted chemical analyses of other bones and teeth found at the sites. Those who lived near Kendrick’s Cave likely ate marine and freshwater foods, while those in Gough’s Cave survived on terrestrial mammals like aurochs and red deer.

Gough’s Cave is also where the remains of Cheddar Man were found. Cheddar Man was a lactose-intolerant person who died in his mid-20s about 10,000 years ago, whose remains were discovered in 1903.

“We knew from our previous work, including the study of Cheddar Man, that western hunter-gatherers were in Britain by around 10,500 years [before present], but we didn’t know when they first arrived in Britain, and whether this was the only population that was present,” said study co-author Selina Brace, a paleobiologist at Britain’s Natural History Museum, in the same release.

The groups in the two caves also had different cultural practices. Decorated animal bones—and no bones with signs of consumption—indicated that the cave in Wales was used primarily for burial, rather than occupation. Meanwhile, chewed bones and skulls fashioned into cups in Gough’s Cave indicate that its inhabitants were ritualistic cannibals.

There’s still plenty to decipher about when people arrived in Britain and how those ancient populations interacted, but the new research clues us in on the origins of two early groups.