The sequencing of the oldest human DNA in the UK so far has shown that two distinct populations of humans lived in Britain following recolonisation at the end of the Ice Age.
The two populations lived only around 1,000 years apart, and yet were found to be genetically and culturally distinct from each other, painting a more complex picture of human populations in the UK 14,000 years ago.
Following the peak of the last Ice Age, human populations in Europe went on the move.
As the warming climate caused more favourable environments in Europe to flourish, the people who had survived along the southern fringes of the continent were able to take advantage of this by moving north, including into Britain.
But what these populations of roving humans looked like, how they moved into these areas and whether they were interacting with each other has been difficult to discern.
New research looking into the genetics of these early settlers has now sequenced the oldest human DNA ever obtained in Britain. The DNA was retrieved from ancient human remains discovered in Gough’s Cave, Somerset, and then compared to other human remains found in Kendrick’s Cave, Wales.
Dr Selina Brace is a Principal Researcher at the Museum who works on ancient DNA.
‘We really wanted to find out more about who these early populations in Britain might have been,’ says Selina Brace. ‘We knew from our previous work, including the study of Cheddar Man, that western hunter-gatherers were in Britain by around 10,500 years ago, but we didn’t know when they arrived in Britain, and whether this was the only population that was present.’
It turns out that these two different sets of ancient human remains show there were two distinct populations – both genetically and culturally – moving around Britain at this time.
The results have been published in Nature Ecology & Evolution.
Changing climates and moving people
Over much of the past tens of thousands of years the climate in Europe has been in flux.
Around 30,000 years ago, a cooling event caused huge glaciers to start to grow in the northern hemisphere. Known as the Last Glacial Maximum, these ginormous icesheets extended their reach over much of northern Europe, forcing surviving plants, animals and any humans into the south.
This would last for around 10,000 years, until a pronounced warming on the continent brought about momentous change.
By 14,000 years ago, the Late Glacial Interstadial was in full swing. This warm period opened up many of the previously uninhabitable regions, as boreal forests began to establish themselves on the once frozen ground and animals started to return.
Following the deer, pigs, aurochs and other prey as it moved north were people. Or so it was thought.
More accurate radiocarbon dating on the human remains from Gough’s Cave in Cheddar Gorge, England, show that the people who lived there were doing so some 300 years earlier than was previously understood. This means that the individuals were living in Britain just before it started to warm.
Professor Chris Stringer is a research leader on human evolution at the Museum.
‘They were actually arriving in Britain while it was still cold,’ explains Chris. ‘Or, alternatively, they were here longer and we’ve just picked them up at Gough’s Cave. Because the date we’ve got doesn’t necessarily mean they were the very first people coming back at this time.’
‘This suggest that there was a population in Britain, even during at least the end of that cold stage.’
What’s more intriguing still is that these people were using objects made of animal remains thought to have already been extinct in Britain at this time, including a baton made from reindeer antler and a spear tip crafted from mammoth ivory.
‘The artefacts are made from cold climate animals which were on the point of disappearing from Britain, or may have even already disappeared by the time the Gough’s people are established,’ explains Chris.
‘This raises several interesting questions: Did they bring these artefacts with them from somewhere colder? Or was Britain even more complicated and still had mammoths and reindeer surviving up in the highlands?’
Either way, as the warming in Europe started to pick up, more people made the journey from the continent to Britain. This including those that would leave behind their remains in Kendrick’s Cave, northern Wales, dated to about 1,000 years after the Gough’s Cave people.
But the genetics of these two populations has revealed something striking.
Despite living relatively close to each other in both time and space, the two human populations are entirely genetically distinct. This means that there were two completely separate populations of humans living in Britain during this period, although it is important to note that it is still unknown if they ever actually overlapped in time.
It is thought that the earlier Gough’s Cave people were more closely related to older human remains found in Belgium, while those from Kendrick’s Cave were closer to a later population in northern Italy.
Separated by culture
But these two populations differed not only genetically, but culturally too.
By looking at the teeth found in both caves, the researchers have been able to build up a more general picture of what the different groups of people were eating. This has revealed that the people living in Gough’s Cave were eating primarily food from the land, such as deer, but that those living near the northern Welsh coast were dining on a diet filled with marine mammals.
Building on this, the tools associated with both sites are also different, as are their apparent funerary practices.
Dr Silvia Bello is a researcher at the Museum who specialises in the evolution of human behaviour.
‘The evidence from the human remains found at Kendrick’s Cave suggests that the cave was used as a burial site by its occupiers,’ explains Silvia. ‘In contrast, animal and human bones found in Gough’s Cave showed significant human modification, which has been interpreted as evidence for ritualistic cannibalism.’
‘This includes human skulls that have been modified into ‘skull-cups’.’
But whether these were ingrained cultural differences found across both populations is almost impossible to tell with current evidence, as these are just two groups of people living in Britain at one point in time.
More information from remains found in other parts of the UK, and further afield into places like France, are vital to filling in these gaps and giving us an even clearer picture of how our ancestors moved around the continent and interacted during the later stages of the last Ice Age.