"But at some point after the Bronze Age, groups in the south-east appear to have mixed with a population similar to those Stonehenge builders who inhabited Britain before the Beakers arrived.
Most people from south-east Britain still trace most of their ancestry to the Beaker people, but the later mixing event had a bigger impact than Medieval Anglo-Saxon migrations - traditionally seen as the foundation point of English history.
Prof Reich said his team at Harvard currently had three working hypotheses to explain the result. While the Beakers replaced around 90% of the ancestry in Britain, it's possible that a pocket (or pockets) of Neolithic farmers held out in isolation somewhere for hundreds of years.
During the Iron Age (which began around 3,000 years ago), they mixed back in with the general population, diluting the Beakers' genetic background with a type of ancestry that's now stronger around the Mediterranean than in Northern or Central Europe.
To date we don't know the weight of the shift back towards 'med' or 'neolithic' or EEF ancient pops; and first BB's never constitued 90% of Britain Bronze pop; someones consider that BB's pushed out the preceding pops, not eradicated them at all (at the contrary, see under); only it seems they left them the worst lands (woodlands) - we have some Britain BBs of some hotspots, and BB's settled for the most on lands not too far from sea, in Britain at least – today Britain pops are not too far from ancient BB’s of the Isles, but this proximity is surely due to more than an historical move from the continent bringing pops which were also close to BB’s auDNA in some way ;
more than an explanation can work here : I believe in a resurgence of old pops which never died out (look at Wales) + some less « steppic »/a bit more « neolithical-like » Celtic tribes of Gaul and Belgia and why not some Roman input ; here we need archeologic details concerning the remnants studied, if they varied from place to place and if the show diverse cultural backgrounds ;
& : picked in Lloyd and Jennifer Laing (1980 it’s true, so some salt ?!?):
« The beakers folk mixed fairly easily and peacefully with the native inhabitants . Beaker pottery is frequently found in megalithic chambered tombs, and beaker association with many of the native monuments of late Neolithic Britain is apparent. In their flint-work they took over some of the traditions of local Neolithic communities and in turn local pottery was influenced by Beaker styles. The fact that some gracile dolichocephalic skeletons have been found in Beakers-style burials indicates that some of the native population adopted a Beaker lifestyle... ». A bit idyllic ?
By the way they say that first allover-corded beakers in Britain were older than on the continent (almost 3000BC) without proved immigration, and that it’s the mix-type (corded-maritime) from the Netherlands which was brought in by immigration around 2500 BC (Round Barrows)...
for the little I know, the most of the identifiable Celtic tribes which put a feet into Britain at those times were from the region between North-East today France and Belgium, maybe Switzerland or close Bavaria, Belgae among them ; I don’t know but I suppose these tribes were not too much « EEFized » at Iron Age what would have been possibly the case for more southern Gaulish tribe a bit later (« not too much » doesn’t mean « not at all ») ; and I suppose it was rather young members among the warriors « low » elites which took part in these adventures, not a lot of slaves (these warriors would have been less mixed than the higher elites which married with locals for political purpose ; that said we don’t know to date the social statute of the studied people in this survey -
what would be interesting is to know if they have splitted out diverse EEF-like pops (more or less ‘iberian’ as opposed to ‘danubian’ or like this) in this southerner component which reappeared...
so : everything is possible, maybe a three-ways EEF ? I put my joker : « wait and see » ;
Agree with Angela that our ancient auDNA diverse analysises don’t disentangle always in a reliable and definitive way the question of WHO send some basic autosomal components and WHEN ; (I hope I don’t mistake her here)
& :I’m aware of no mention about Hallstatt or La Tène auDNA at hand or I passed over something ?