This quote from
the paper (Sanchez-Quinto et al, 2019):
"Interestingly, we also found a significant farmer-specific genetic
affinity between the British Isles Neolithic populations and the
Scandinavian populations"
Yeah,
about that. This issue, as I've complained or wondered many times last year, is that many British farmers might have already been shifted towards Southern Scandinavia and its other outpost, the Netherlands, because of
the Peterborough FOLK. Heard it here first. Whatever the final number, there's no doubt Beakers were storming the beaches of the Isles and pretty much flattened everything in their way, but 93%? Food vessels?!
The number might go up or down. No clue, but we'll see.
The conclusion of the paper, is Scandinavian farmers had western European admixture not the other way around. Actually, Eurogenes's G25 Global PCA picks this up as well.
ReplyDeleteRegardless, couldn't that skew the ~93% replacement figure later on? BTW, I never said before that'd be the case, but it's a question I have.
DeleteNot necessarily all that much. The 93% replacement figure involves detection of what is basically a steppe signal. The Neolithic signal in Scandinavia and the British Isles should look much more similar to each other than either of them do to the replacing Bell Beaker populations.
DeleteAlso, keep in mind that the 93% replacement was made possible, in large part, because of apocalyptic scale failures to the Neolithic farmers to be able to sustain themselves as farmers, either due to a weather event, or given the way that the failures work their way over a number of years across Europe, perhaps because the Neolithic farmers were exhausting the soils and didn't know how to fertilize or let land lie fallow to fix it. The British Isles, after first being swept by Neolithic farmers everywhere replacing most hunter-gatherers, then saw their populations collapse as their returned to a life with hunting and gathering providing more sustenance than farming in most places, and with the residual hunter-gatherer populations share of the gene pool surging as the hunter-gatherers became the higher status, more selectively fit population again. So, the Bell Beaker people were surging into the vacuum created by a society's collapse, which makes 93% replacement by people who actually do know how to farm sustainably less remarkable. Part of the "replacement" which is actually just a percentage point change in "market share" of the gene pool, probably came from simply outnumbering an almost hunter-gatherer society with a sustainable farming based society that support much higher population densities. This doesn't mean that there wasn't genocidal slaughter that killed men and seized the remaining women, but in a scenario where the Bell Beaker people are swooping into a post-apocalyptic world by Neolithic standards, the slaughter component of the turnover doesn't need to be nearly so complete to have the same practical effect.
DeleteSee my comment to Matt. The turnover is undoubtedly large, but the composition of the Neolithic ancestry and the assumptions for the level of steppe ancestry in incoming Beakers might change that number some.
Delete93% replacement is based on on steppe ancestry as andrew notes and assuming incoming groups had same steppe ancestry as Dutch Beakers (mean date around 2138 BCE) moving into Britain around 2500 BCE (58.1% Steppe_EBA). If moving in ("intrusive"?) groups had more (e.g. like CWC Germany - 70.6% Steppe_EBA), then more ancestry of Brit Beakers (54% Steppe_EBA) / Brit MBA (50.7%) / Brit LBA (47.8%) would be likely / possible to be local.
ReplyDelete54/58 = 0.93, therefore 93% replacement. If more like 54/71 = 0.76, then 76% replacement.
Even though the Netherlands Beakers are largely later than the Brit Beakers, certainly than the earliest, it is a defensible assumption to use them as the mixing population since they are fairly homogenous and have the correct archaeological designation and y-haplo.
However, there was some talk of a French Beaker sample who R1b-L11 who was akin to Corded Ware Germany in steppe ancestry - https://indo-european.eu/2018/11/a-very-yamnaya-like-east-bell-beaker-from-france-probably-r1b-l151/.
So if that's the case, IMO you could question whether the Netherlands late Beakers are really a good proxy and you shouldn't be modelling pop replacement in Britain with a sample like that.
Also note that among the Brit Beakers, one of the earliest samples I2417 models with 1.18% Dutch Beaker ancestry, which implies a steppe level of 68.7%. The other two earliest have 80% Dutch Beaker (46% Steppe), and 59.5% Dutch Beaker (34.5% Steppe).
In any case, you're probably only talking about 25% survival in British Beaker set, at max. (But that may be more compatible, ultimately, with the archaeology. If it happens.).
(All the figures from supplement - https://media.nature.com/original/nature-assets/nature/journal/v555/n7695/extref/nature25738-s2.pdf).
Re; Peterborough folk, that's interesting. Perhaps they would have to see if post 3300 BCE Britain Neolithic samples (not many) form a clade with pre-3300 BCE wrt Sweden_MN. If they do, then tough to see that any population movement can happen in that direction. Perhaps the sample count is not good for this though.
Yeah, not implying or positioning for one outcome either way. I just though the original figure was a bit premature given the resolution of Neolithic Britain was fairly low and there was a presumption that the Neolithic ancestry would be monolithic. Also, as you've mentioned, it's possible that some of the incoming Beakers had higher steppe ancestry than what we've seen in the Netherlands, which by the way contributes massively to the Isles in an archaeological sense anyway. But this leaves the possibility that more Neolithic ancestry survived than is currently presumed.
DeleteThe coverage of Neolithic Britain is quite extensive compared to other regions/time periods. Neolithic Brits were a uniform bunch. They probably descend from a handful of common European continental ancestors who 'replaced' the few hunter gatherers that lived there before them. That was the conclusion of a paper from a few days ago.
DeleteBrace 2019
Ancient genomes indicate population replacement in Early Neolithic Britain
https://www.nature.com/articles/s41559-019-0871-9
Holy Crap, too much DNA!
Delete@Sam,
DeleteI read through all the supplementary material of the Brace paper and actually I was just checking out the two individuals that were buried with Peterborough. I do see that the Brace people mention that Brits are indeed very Aegean-Iberianesque. Not questioning that, just a separate phenomenon beginning in the MN. I didn't much of any difference between Cog and Jubilee and the others and I'm not sure how their statement squares with Sanchez-Quinto et al regardless of the directionality. I may have to read it a few times.
The resurgence of WHG genes that Andrew describes above occurred in Continental Europe but according to this week's paper by Brace et al specifically did NOT happen in the British isles. Moreover, what replaced early arable farming in the British neolithic was a pastoral economy rather than a return to hunting & gathering, according to what I've read.
ReplyDeleteIs there any real evidence for the "population collapse" theory for the Beaker takeover in Britain? To the resolution of current dating, immediately prior to the beaker arrival, i.e. c 2500 BC, the local population produced Stonehenge 3 II, i.e. the sarsen circle and trilithons, along with the superhenges at Avebury and Marden, and the mounds at Silbury, Marlborough and Marden. The excavations from Durrington Walls strongly imply that this was organized on an island-wide level given that livestock consumed in the feasting comes from as far away as Scotland. It is very hard to reconcile this with a picture of a society in apocalyptic collapse.
Of course the timing allows all this work to have been organized by the Beakers rather than the neolithics, but archaeologists don't seem to like this idea, presumably because it's associated with Grooved Ware. Then again the Beakers obviously adopted Stonehenge despite the fact that the whole henge/circle thing was entirely insular and predated their emergence by half a millenium.
Finally, on 93% replacement, how confident can we be that this does not just refer to the elite group? Aren't most of the sequenced bones from high-status graves? (including the "ancestors" in the megalithic tombs which per Sanchez-Quinto et al are clearly not a random cross-section of the neolithic population.)
Re; what Brace and Olalde's data say on andrew's idea, I think it may be the case that these basically don't have the data to test andrew's hypothesis (in terms of anything at all supporting it, or anything clearly rejecting it).
Deleteandrew's hypothesis I think is, as farming failed, *then* we would see "the residual hunter-gatherer populations share of the gene pool surging as the hunter-gatherers became higher status".
Now, the "Did farming fail?" claim of fall in cultivation places fall to very low cultivation largely after 3300 BCE, and cereal only really 'stops' after 3000 BCE - https://img.scoop.it/r9jHKX7xpWE27hX3_wE2ZIXXXL4j3HpexhjNOf_P3YmryPKwJ94QGRtDb3Sbc6KY. (" Between 3300 and 1500 BC Britons became largely pastoral, reverting only with a major upsurge of agricultural activity in the Middle Bronze Age.")
The British ancient samples pre-2500BCE are largely prior to 3300 BCE - https://i.imgur.com/z4Of3an.png.
Or see - https://i.imgur.com/dvZNt3H.png.
Note also that those that are later than 3300 BCE are largely from the Orkney and culturally related regions of North Scotland, where it seems more agreed that farming did *not* fail, and andrew's hypothesis wouldn't really operate anyway (cite - https://www.tandfonline.com/doi/abs/10.1080/00438243.2015.1072477?journalCode=rwar20).
There's almost nothing from England and Wales, certainly nothing with high sample quality, after 3000 BCE until steppe admixed samples around 2500BCE.
This above just Olalde, but I don't think Brace has a lot of later samples, esp. outside of North Scotland. Outside of N Scotland, browsing her supplement data, I think there's one extra late neolithic Welsh sample, I5357, and one English sample I5387. (Some of Brace's dating intervals seem ridiculously large, e.g. 4000-2500 BCE???).
So it's hard to test.
On circumstantial evidence though, I think the idea seems wrong - when we see what look like admixed individuals in the Beaker Britain set, they do not look like they are admixing with a population with a lot more HG ancestry than the pre-3300 BCE Neolithic British set. They look like LN British farmers + later Dutch Beakers, not a WHG rich population + later Dutch Beakers (all caveats above about whether the latter is actually a good proxy applied). And the very few English and Welsh samples in the period of "failure of farming" do not look particularly enriched in HG ancestry.
Was looking at those graphics Reich used in his presentations last year for plotting Beaker_NLD ancestry in Britain against time.
ReplyDeleteSlightly dissatisfied with how they "ceiling" Beaker_NLD ancestry at 100, even though it goes above that, so used the Table S9 and Fig 2 in Olalde 2018 to produce these: https://imgur.com/a/Yu9P0Pj
May be of interest for looking at particular samples.
The “failure of farming” in Britain occurred during the tenure of the one and the same Population- the I2 - rich middle neolithics of Britain
ReplyDeleteFuller’s figures are pretty convincing- the decline of crops after 3000 BC are marked
However how does this translate into demography ? The post 3000 BC period was the peak of Henge building - was this the last throes of to appease the gods ?
Curiously, in Scandinavia after 3000 BC, megaliths are no longer built and there is suggestion of soil exhaustion
So whilst pre-existing population decline explains some aspects of BB transition, it does not explain all- such as Iberia and France; where no such crises are discernible . In fact; they seem to have been doing quite well
Dorian Fuller is indeed the main person marshaling evidence in favor of the failure of farming hypothesis. I'd forgotten that he was the source of it for a moment.
DeleteThanks for the information! Here in Germany is still the doctrine of the Becherherkunft from Hungary. I fight against that. I believe in the first great empire and the first high culture in Western Europe by the R1b Bellbeaker people, for example: http://atlantischeseuropa.blogspot.com/2017/11/the-bell cup culture-the-first.htmlHowever, I turn to interested lay people and not to professionals.Greetings, Achim Hess
ReplyDelete