Scientists have recently uncovered ancient human remains in Wales and England that rank among the oldest DNA ever identified in Great Britain. The findings trace separate DNA strands back to two different ancestral groups that likely migrated to the area toward the end of the most recent ice age. At the time, Great Britain was connected to continental Europe by a land bridge called Doggerland that was gradually submerged beneath the North Sea about 6,000 years ago.

The study “Dual ancestries and ecologies of the Late Glacial Palaeolithic in Britain” was published this week in the journal Nature Ecology & Evolution,

“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,” Mateja Hajdinjak, a geneticist specializing in ancient DNA at the Francis Crick Institute, said in a statement.

The remains identified at a site in Gough’s Cave, Somerset, England, date back to around 15,000 years ago and show evidence of a mammal-based diet. Those found in Kendrick’s Cave, Wales, are approximately 13,500 years old and point to freshwater food sources, according to The Guardian.

Gough’s Cave is the same location where researchers unearthed a 10,000-year-old skeleton, dubbed Cheddar Man, in 1903. The remains belonged to a lactose-intolerant Mesolithic hunter-gatherer who had died in his mid-20s.

“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,” Selina Brace, a co-author on the report and paleobiologist at Britain’s Natural History Museum, said.