Brit-Am Anthropology and DNA Update
[Note: Brit-Am does not agree with the dates given in the articles below but (apart from that) the historical scenarios may be worth considering].
Contents:
1. (a) Ancient mass migration transformed Britons' DNA
1. (b) Ancient Britons 'replaced' by newcomers
2. DNA study reveals Ireland's age of 'god-kings'
^^^^^^^^^^^^^^^^^^^^^^^
1. (a) Ancient mass migration transformed Britons' DNA
https://www.bbc.com/news/science-environment-59741723
By Paul Rincon
Science editor, BBC News website
Extracts:
The migrants brought new ritual practices into Britain such as hoarding bronze objects in the ground.
Scientists have uncovered evidence for a large-scale, prehistoric migration into Britain that may be linked to the spread of Celtic languages.
The mass-movement of people originated in continental Europe and occurred between 1,400 BC and 870 BC.
The discovery helps to explain the genetic make-up of many present-day people in Britain.
Around half the ancestry of later populations in England and Wales comes from these migrants.
It's unclear what caused the influx of people during the Middle to Late Bronze Age, but the migrants introduced new ritual practices to Britain.
The results, published in the peer-reviewed journal Nature, are based on DNA extracted from 793 ancient skeletons.
The study reveals that a gene allowing some people to digest raw milk increased rapidly in Britain during the Iron Age - 1,000 years before the same thing happened elsewhere in Northern Europe. It's an extraordinary example of natural selection for a genetic trait, and the reasons for its spread remain a mystery.
^^^^^^^^^^^^^^^^^^^^^^^
1. (b) Ancient Britons 'replaced' by newcomers
https://www.bbc.com/news/science-environment-59741723
It's evidence for pioneer settlement of the region from the continent, starting as far back as 1,400BC.
At first, said Dr Thomas Booth, from the Francis Crick Institute in London, people with the new, continental ancestry "appear almost exclusively in Kent... but we don't really see them anywhere else and we don't see a change in the overall ancestry of Britain.
But the new DNA signature soon spreads: "From around 1,000BC, suddenly that ancestry seems to disperse all the way through southern Britain, particularly," he explained, adding: "There's no particular genetic change in Scotland, but everywhere in England and Wales, this ancestry has an effect."
Prof David Reich from Harvard Medical School in Cambridge, US, who led the research, told BBC News: "We estimate that about half the DNA of people in the Iron Age in Britain comes from these new migrants. What that means is if you trace back the ancestors of these Iron Age Britons 20 generations before the time they lived, half of them would not be living on the island of Great Britain."
As for where the initial migrants originated in continental Europe, their closest matches are with ancient populations in France. But says Prof Reich, "We don't yet have adequate sampling to directly confirm that or to see where exactly in France it would be."
When the newcomers arrived, the existing British population traced most of its ancestry to people who arrived at the end of the Neolithic, around the time Stonehenge was being built. They were part of a tradition known as the Beaker Culture.
The later, mid- to late Bronze Age movement of people brought new cultural practices to the country. This included the intentional burial of multiple Bronze objects - known as hoards - perhaps as offerings to the gods.
Also intriguing is the new study's finding that there was a rapid increase - during the Iron Age - in the frequency of a gene variant for digesting raw milk, something that's commonly known as lactose tolerance.
"It remains rare in Britain until the middle of the Iron Age, about 2,500 years ago. It's incredibly recent in evolutionary terms. In order for it to have gone from nothing to almost everybody in that period of time, your ability to digest raw milk must have been life or death," said Tom Booth.
"Adding to this whole craziness to some extent is that it becomes common in Britain 1,000 years before it becomes common elsewhere in Northern Europe."
He added: "One of the leading possibilities is maybe that Britain went through a period of catastrophe like a famine or difficulty acquiring clean water sources. Then, what raw milk does is supply you with a clean source of hydration and food at the same time. Potentially, all you need are cows or sheep and you can make it through a disaster like that."
The mass-movement of people to Britain took place against the background of similar upheaval on the continent which, to some extent, homogenised the genetic make-up of Europeans.
"In this period there's convergence of ancestry throughout western and central Europe," said Prof Reich.
"In general, though there were exceptions, northern populations become more genetically similar to southern populations. And the southern populations become somewhat genetically more similar to the northern populations."
He said the exceptions were Scotland and the island of Sardinia, which were not as impacted by this North-South exchange.
^^^^^^^^^^^^^^^^^
2. DNA study reveals Ireland's age of 'god-kings'
https://www.bbc.com/news/science-environment-53059527#:
Extracts:
The Newgrange monument in County Meath is a kidney-shaped mound covering an area of more than one acre. It's part of a tradition of elaborate monuments built with large stones, or megaliths, in Atlantic Europe during the Neolithic.
Older than Stonehenge and the Pyramids of Giza, the site is famous for its annual solar alignment where the winter solstice sunrise illuminates the inner chamber in a blast of light.
"The prestige of the burial makes this very likely a socially sanctioned union and speaks of a hierarchy so extreme that the only partners worthy of the elite were family members, said Prof Dan Bradley, also from Trinity College.
Dr Cassidy, who is first author of the new study published in Nature, told BBC News: "It's an extreme of what elites do - marrying within your kin group allows you to keep power within your 'clan',
Remarkably, a local myth resonates with both the DNA results and the Newgrange solar phenomenon. The story was first recorded in the 11th Century AD - four millennia after the construction of Newgrange - and tells of a builder-king who restarted the daily solar cycle by sleeping with his sister.
The Middle Irish place name for the neighbouring Dowth passage tomb, Fertae Chuile,
is based on this lore and can be translated as "Hill of Sin".
The team unearthed a web of distant familial connections between the man from Newgrange and other individuals from passage tomb sites across the country, including the "mega-cemeteries" of Carrowmore and Carrowkeel in County Sligo.
"It seems what we have here is a powerful extended kin-group, who had access to elite burial sites in many regions of the island for at least half a millennium," explained Dr Cassidy.
Tom Booth said: "In Britain, recent discoveries that some tombs were built over the remains of timber houses has been used to suggest that these sites were linked to particular families, but solid evidence for who ended up in these tombs and why has always been elusive."
Ireland's Neolithic inhabitants traced their origins to an expansion of people out of Anatolia (modern Turkey) around 6,000-7,000 years ago. This migration transformed Europe's way of life from one focused on hunting to one based on agriculture. Genetically, Ireland's first farmers were most closely related to people living at broadly the same time in Iberia (modern Spain and Portugal).
Over generations, the farmers traversed the Mediterranean from Anatolia to Iberia, weaving their way up the French coast before making their way to Ireland by sea.
On reaching the shores of this North Atlantic landmass, the new migrants quickly displaced the local Mesolithic hunter-gatherers, who were genetically similar to pre-farming peoples across Europe. However, their DNA shows they developed a distinctive character after being isolated for centuries.