London Museum from 2015
From the end of the Roman occupation through the Anglo-Saxon and Viking invasions – a new way of testing DNA in ancient bones could force a rethink of key moments in Britain’s early history, say researchers.
Scientists could already track big alterations in DNA that occur over thousands or millions of years, helping us learn, for example, how early humans evolved from ape-like creatures.
Now researchers can identify subtler changes over just hundreds of years, providing clues as to how people migrated and interacted with locals.
They are using the new method to analyze human remains found in Britain, including from the time when Romans were replaced by an Anglo-Saxon elite from Europe.
Prof Peter Heather, from Kings College London, who is working on the project with the developers of the new DNA technique at the Francis Crick Institute in London, said the new technique could be “revolutionary”.
While the project will analyze the DNA of more than 1,000 ancient human remains of people who lived in Britain during the past 4,500 years, researchers have homed in on the time after the Romans left as a particularly interesting era to study.
What happened in this period more than 1,500 years ago is unclear from written and archaeological records. Historians are divided in their views about the scale and nature of the Anglo-Saxon invasion, whether it was large or small, hostile or co-operative.
“It is one of the most contested and therefore one of the most exciting things to work on in the whole of British history,” according to Prof Heather.
“[The new method] will allow us to see the type of relations that are being found with the native population,” he said. “Are they co-operative, is there interbreeding, are the locals able to make their way into the elite?”
The problem the researchers were trying to overcome is that a human’s genetic code is extremely long – consisting of 3 billion separate chemical units.
Spotting the small genetic changes in that code which occur over a few generations, for example, as a result of new arrivals interbreeding with the local population, is like looking for a needle in a haystack.
The researchers solved the problem by, as it were, taking away the haystack and leaving the needle in plain sight – they found a way to identify the older genetic changes, disregard them and look only at the most recent alterations.
They combed the genetic data of thousands of human remains from an online scientific database, then calculated how closely they were related to each other, which chunks of DNA were inherited from which groups and when.
This created a family tree with older changes appearing in earlier branches, and more recent changes showing up in newer ‘twigs’, hence the name Twigstats.