by Mark Waghorn, SWNS

Mass migration across the English Channel from Europe is nothing new as immigrants replaced half the population of England and Wales during the Late Bronze Age, suggests new DNA research.

Large scale movements into southern Britain 3,000 years ago have been tracked for the first time.

The people included those looking for husbands or wives - changing around 50% of the genes of the subsequent population.

The findings are based on an analysis of the DNA of almost 800 ancient individuals, the biggest survey of its kind.

Lead author Professor Ian Armit of the University of York said: "We have long suspected, based on patterns of trade and shared ideologies, that the Middle to Late Bronze Age was a time of intense contacts between communities in Britain and Europe.

"While we may once have thought that long-distance mobility was restricted to a few individuals such as traders or small bands of warriors, this new DNA evidence shows considerable numbers of people were moving across the whole spectrum of society."

Combining genetics and archaeology, researchers discovered that rather than a violent invasion or a single event, there was sustained contact between mainland Britain and Europe over several centuries.

Reasons included intermarriage and small-scale family groups upping sticks. The new arrivals became completely mixed into farming communities in the period 1,000 to 875 BC.

They are most likely to have come from communities in and around present-day France. The Middle to Late Bronze Age was a time when agriculture expanded across southern Britain.

Extensive trade routes developed to allow the movement of metal ores for the production of bronze. These new networks linked wide-ranging regions across Europe, as seen from the spread of bronze objects and raw materials.

Some of the earliest genetic outliers have been identified in Kent, suggesting the south-east was a key focal point. This resonates with the discovery of Cliffs End Farm in Thanet - an archaeological site which includes Bronze Age enclosures and an Anglo-Saxon cemetery.

Some individuals were shown to have spent their childhoods on the continent.

The study in the journal Nature also strengthens the case for early Celtic languages arriving in Britain during the Bronze Age. It contradicts the theory that they emerged in the subsequent Iron Age when there was much less migration.

Co-author Professor David Reich of Harvard Medical School in Boston, USA, said: "These findings do not settle the question of the origin of Celtic languages into Britain. However, any reasonable scholar needs to adjust their best guesses about what occurred based on these findings.

"Our results militate against an Iron Age spread of Celtic languages into Britain - the popular 'Celtic from the East' hypothesis - and increase the likelihood of a Late Bronze Age arrival from France, a rarely discussed scenario called 'Celtic from the Centre'.

"By using genetic data to document times when there were large-scale movements of people into a region, we can identify plausible times for a language shift.

"Known Celtic languages are too similar in their vocabularies to plausibly descend from a common ancestor 4,500 years ago which is the time of the earlier pulse of large-scale migration. Very little migration occurred in the Iron Age.

'A further unexpected finding was a large increase in the frequency of lactose tolerance'

"If you're a serious scholar, the genetic data should make you adjust your beliefs: down-weighting the scenario of early Celtic language coming in the Iron Age and early Bronze Age and up-weighting the Late Bronze Age."

A further unexpected finding was a large increase in the frequency of a mutation for lactose tolerance - the ability to digest milk, cheese and other dairy products in Bronze Age populations in Britain compared to the continent.

Co-senior Professor Ron Pinhasi, a specialist in ancient DNA at Vienna University, said: "This study increases the amount of ancient DNA data we have from the Late Bronze and Iron Age in Britain 12-fold and Western and Central Europe by three and half times.

"With this massive amount of data, we have for the first time the ability to carry out studies of adaptation with enough resolution in both time and space to allow us to discern that natural selection occurred in different ways in different parts of Europe.

"Our results show dairy products must have been used in qualitatively different ways from an economic or cultural perspective in Britain than they were on the European continent in the Iron Age, as this was a time when lactose persistence was rising rapidly in frequency in Britain but not on the continent.”

The data also indicates population movements between different parts of continental Europe.

It confirms what archaeologists have long suspected - the Late Bronze Age was a period of intense and sustained contacts between many diverse communities.

Professor Reich added: "This shows the power of large-scale genetic data in concert with archaeological and other data to get rich information about our past from a time before writing.

"The studies are not only important for Great Britain, where we now have far more ancient DNA data than in any other region but also because of what they show about the promise of similar studies elsewhere in the world."