Dear people of the British Isles, almost none of your ancestors were part of the hunter-gatherer population that lived there from 11,000 years ago. Fewer than one in a thousand of you have local ancestry going back that far.
So who do the people of Britain and Ireland descend from if the aboriginal Britons effectively went extinct?
You descend mainly from early European farmers, and it's tempting to think that you descend from the early European farmers who reached the British Isles about 6,000 years ago, who in turn descended from Anatolian farmers. In the space of a few hundred years these early European farmers replaced more than 99 percent of the aboriginal British population.
But you don't descend from them either. That isn’t why you have DNA from early European farmers. It isn’t end of the story, it’s the beginning.
Over time, new research shows, there were additional massive migrations to the islands, again replacing almost the whole population, and now, fewer than one in 30 people in England now can trace their origins to Britain’s first farmers.
Yet the people of the British Isles still have a large chunk of their ancestry from early European farmers. How could that be?
The extraordinary origin story of the British has unfolded in a series of papers over the last few years, mostly recently with the discovery of a massive influx to the isles about 3,000 years ago – via France, no less. The existence of this incursion was deduced by a vast multidisciplinary team led by Prof. David Reich of Harvard University, a leading expert on human population genetics.
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This influx, however, was largely confined to the south and center of the island, hardly reaching Scotland, the genetic evidence indicates. So who are the Scots? We’ll get to that.
Exit from Turkey
Britain has been peopled for almost a million years. Through the first half million years and at various times later when sea levels were low, Britain was connected to the European mainland. Hominins, early human ancestors, could just walk there. The earliest evidence of a hominin presence is stone tools and footprints found on the Norfolk coast in the southeast. Actual bones, classified as Homo heidelbergensis, have been discovered in Sussex in the south and were dated to half a million years. Neanderthals arrived too, at least 400,000 years ago.
By 40,000 years ago the Neanderthals had gone extinct in Britain, and modern humans had arrived. They did not last long.
The modern human presence in Britain was a function of swinging climate. During the last Ice Age, most of Britain was glaciated, and likely all of it was uninhabitable. But it was connected to Europe by Doggerland, a large region of the North Sea that is shallow and becomes dry land when sea levels are low, as occurs when water gets locked up in glaciers during ice ages. About 14,000 years ago, as the glaciers began to recede from Britain, both animals and humans crossed the land bridge again.
The islands have been occupied by humans without interruption since that time. By 11,000 to 12,000 years ago, Britain was occupied permanently by hunter-gatherers from the Continent. Traces of their settlements have been found, one famous instance being the Star Carr site in Yorkshire in northern England, home of the deer skull masks.
At about that time, over in the Levant and the wider Middle East, the Neolithic Revolution was beginning: a gradual transition from a lifestyle of hunting and gathering to subsistence agriculture. The innovation spread to Anatolia in southern Turkey, and subsequently onward to Europe about 8,500 years ago, Reich explains.
Possibly because farming could support much larger populations and more rapid population growth than hunting and gathering, the early farmers radiated out beyond Anatolia, where they met with and mixed with European hunter-gatherers. And about 6,000 years ago, early European farmers with a touch of European hunter-gatherer inside reached Britain and Ireland. This did not augur well for the locals.
“It was an extremely disruptive event for the local population,” Reich says, which is one way to put the 99 percent replacement of the local hunter-gatherers.
We don’t know what happened. It could have been extreme violence, or perhaps the newcomers brought germs to which the locals had no resistance, or simply that with their advantageous newfangled farming, they could be fruitful and multiply much more than the local foragers, Reich notes. Effectively, the local hunter-gatherers went all but extinct and were supplanted and absorbed by farmers most of whose ancestors hailed, many generations before, from Turkey, genetic analyses show.
Purely archaeological finds cannot connect these early farmers in Britain with the early farmers of Anatolia – thousands of years passed between the exit from Turkey and the arrival in Britain, co-author Ian Armit explains. Between the Anatolian agriculturalists and the first Britons farming, there were many cultural transformations.
But these early farmers did bring innovations with them observable in the British archaeological record; for example, they introduced polished stone tools and pottery, and may have introduced large wooden structures. They also brought the cow and other domestic animals and plants to the island, Armit says.
And there matters stood until the dawn of the Bronze Age, about 4,500 years ago, when Britain experienced a massive influx of people who traced most of their ancestors to horse-riding nomads of the Eurasian steppes: the Yamnaya.
The Yamyana were among the early adopters of the horse, and had begun expanding out of the steppe north of the Black and Caspian seas about 5,000 years ago. The nomadic Yamnaya and their animals went in all directions, galloping from Hungary into Mongolia in the one direction and rolling into Europe in the other.
This was how so-called Bell Beaker traditions from Europe reached the islands. And the interlopers nearly replaced the entire population – at least 90 percent.
So one would expect today’s English to be pretty direct descendants of people who brought the Bell Beaker culture to the British Isles, no?
But they are not. Today’s English – the people who live in the southeast of the island of Britain – have more ancestry from early European farmers, and also, more than Scots do. How did that happen?
Blame the French
The answer lies in the researchers’ revelation: a third and previously unknown major migration of people into southern Britain during the Middle to Late Bronze Age, between 2,800 and 3,300 years ago. It too was heavily disruptive, changing the population’s ancestry by about half. In the south of the island. Not the north – not Scotland.
Where did these people come from? France, most likely: genetically the southern British in the Late Bronze Age are most similar to Late Bronze and Iron Age populations in France, the analyses show.
Who were these newcomers? They were people who like contemporary Brits were a mixture of Yamnaya and early European farmers with a trace of European hunter-gatherer. But they had a little more early European farmer than did the Brits – a subtle pattern but enough to allow the researchers to figure out what happened.
All this came to light because Reich and colleagues noticed in 2016 that southern and northern Brits today have different percentages of DNA from early-European farmer and steppe people.
“We knew from genetic data that in the Early Bronze Age, after the Beaker culture arrived, the proportions of steppe ancestry and farmer ancestry were the same in northern and southern Britain,” Reich says. “Something happened from 4,500 years ago to the present that raised the proportion of farmer ancestry in southern Britain but not in Scotland. Clearly something big happened. We didn’t know what it was but knew it wasn’t the Saxons because they have less farmer ancestry than the English do.”
Mightily perplexed, the team collected more genetic data from the relevant Late Bronze Age and Iron Age in Britain, and central and western Europe for comparison. They concluded that there had been an influx of people descending from the early European farmers to southern England about 3,000 years ago (the Late Bronze Age), but their descendants hardly reached Scotland.
They quite likely came from France, and earlier migrations may have come from more northern places like the Netherlands. “A French origin is likely but not proven, as there is not yet ancient DNA from France comparable to Britain,” Reich says.
So who are the Scots and Irish? They are more direct descendants of the steppe Bell Beaker migrants about 4,500 years ago, with less impact from later migrations.
Reich paints this extreme population turnover on a familiar backdrop: Stonehenge.
The builders of Stonehenge
Stonehenge was built by descendants of the first influx of early European farmers. But these farmers were then replaced by descendants of the steppe people. These in turn were largely replaced by a fresh influx of people with more ancestry from the early farmers.
So, the British today do not descend in any quantitatively important way from the people who built Stonehenge, Reich concludes. “These discoveries from 2018 and 2019 were huge surprises because of the extent of population turnovers,” he says.
And there were later influxes, Reich notes, such as the Saxons, who brought proto-English to England 1,600 years ago after the Romans withdrew, and this also resulted in a pretty hefty population turnover. And perhaps there were still other movements of people yet undiscovered.
One upshot is that only less than 0.1 percent of the ancestry in Britain is from the original hunter-gatherers who arrived as the Ice Age waned. Another is that the British, French and Turks have more in common than they might have thought.
A third and major conclusion is that the whole idea of original biological descent giving people today an inalienable right to live in a place is nonsense. “In any given place in the world, the idea of continuity from prehistory, of purity, is hard to maintain in light of the genetic data,” Reich says. The evidence is overwhelming that today’s populations are for the most part the result of large-scale movements from faraway regions.
“The people in any one region almost always have very little ancestry from those who lived in the same region thousands of years before,” he says.
Strangely perhaps, following the mass migrations at the dawn of the Bronze Age, in the subsequent Iron Age there seems to have been less movement from the Continent to Britain. This may be because to make bronze, you need copper ore, which is rare and therefore was traded at long distances. But iron ore is, literally, like dirt.
While this part is speculative, there is direct evidence that international voyaging slowed during the Iron Age: the extraordinary lack of migration into Britain in this period compared to the previous Late Bronze Age and differences in the ability or lack thereof to delight in dairy.
Mammals are born with enzymes called lactase enabling them to digest their mother’s milk. The baby’s body stops producing these enzymes after weaning. But as we domesticated herbivores and began utilizing them not only for meat but for milk, we gradually developed “lactase persistence” – our ability to consume milk without becoming a social liability.
Reich and the gargantuan team had another surprise to spring: About 2,300 years ago about 50 percent the British were lactase persistent, compared with less than 10 percent of central Europeans.
In continental Europe, lactase persistency would only become widespread a thousand years and more later. Today about 70 percent of Britons are lactase persistent compared with 50 percent in central Europe: Hungary, Croatia and so on, Reich says.
All this indicates that Britain was isolated during the Iron Age and that those early Brits used milk intensively, which is known not only from their enzymatic ensemble but also from analysis of plaque on ancient teeth and residues on ancient pots. But continental Europeans were also using milk based on the archaeological evidence in the Iron Age. Either Iron Age continental Europeans were macho about stomachache and flatulence, or they began by turning milk into more digestible yogurt and cheese.
In any case, it seems Britain and the Continent had distinctly different cultural and biological trajectories during the Iron Age.
Finally, this sweeping series of studies may shed light on how early Celtic languages reached Britain: with that hitherto unknown third migration about 3,000 years ago of people who apparently came through France.
All this information comes from an enormous amount of accruing research including the whole-genome analysis of 793 ancient people mostly from the Middle and Late Bronze Age and Iron Age. These people lived in Britain as well as central and western Europe. In this way, the third massive influx was exposed, with cherries on top.
One cherry is an outlier known as the Amesbury Archer, aka the King of Stonehenge, the richest burial in that mortuary landscape, Reich says. Isotopic analysis of his bones and teeth before the genetic study revealed something startling. British, he was not. He was a migrant from the Continent, most probably from southern Scandinavia or the foothills of the Alps.
“He’s from a time we know of mass migration,” Reich says. “He’s interesting because he is clearly a migrant.”
Judging by the manner of his interment, he was privileged – and buried right next to him was another person whom the archaeologists have called the archer’s companion. The two shared a bone malformation in their foot that suggested that they might be related. But genetic analysis showed they weren’t.
The shared deformity could have been coincidental. And the kicker is: The Amesbury Archer had too much farmer ancestry and not enough Yamyana ancestry to belong to the main stream of migrants who replaced more than 90 percent of Britain’s ancestry, Reich says. We are to conclude that people at the time really got about a lot.