Continental immigration and the persistence of Neo male lineages in BA Orkney.

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Ancient DNA at the edge of the world: Continental immigration and thepersistence of Neolithic male lineages in Bronze Age Orkney

Katharina Dulias, M. George B. Foody, PierreJusteau, Marina Silva, Rui Martiniano, Gon

https://www.pnas.org/content/119/8/e2108001119


Significance



The Orcadian Neolithic has been intensively studied and celebrated as a major center of cultural innovation,whereas the Bronze Age is less well known and often regarded as a time of stagnation and insularity. Here, we analyze ancient genomes from the Orcadian Bronze Age in the context of the variation in Neolithic Orkney and Bronze Age Europe. We find clear evidence for Early Bronze Age immigration into Orkney, but with an extraordinary pattern: continuity from the Neolithic on the male line of descent but immigration from continental Europe on the female side, echoed in the genome-wide picture. This suggests that despite substantial immigration, indigenous male lineages persisted for at least at thousand years after the end of the Neolithic.



Abstract


Orkney was a major cultural center during the Neolithic, 3800 to 2500 BC. Farming flourished, permanent stone settlements and chambered tombs were constructed, and long-range contacts were sustained. From ∼3200 BC, the number, density, and extravagance of settlements increased, and new ceremonial monuments and ceramic styles, possibly originating in Orkney, spread across Britain and Ireland. By ∼2800 BC, this phenomenon was waning,although Neolithic traditions persisted to at least 2500 BC. Unlike elsewhere in Britain, there is little material evidence to suggest a Beaker presence, suggesting that Orkney may have developed along an insular trajectory during the second millennium BC. We tested this by comparing new genomic evidence from 22 Bronze Age and 3 Iron Age burials in northwest Orkney with Neolithic burials from across the archipelago. We identified signals of inward migration on a scale unsuspected from the archaeological record: As elsewhere in Bronze Age Britain, much of the population displayed significant genome-wide ancestry deriving ultimately from the Pontic-Caspian Steppe. However,uniquely in northern and central Europe, most of the male lineages were inherited from the local Neolithic. This suggests that some male descendants of Neolithic Orkney may have remained distinct well in to the Bronze Age, although there are signs that this had dwindled by the Iron Age. Furthermore, although the majority of mitochondrial DNA lineages evidently arrived afresh with the Bronze Age, we also find evidence for continuity in the female line of descent from Mesolithic Britain into the Bronze Age and even to the present day.




Results

We present shotgun genome data from 29 samples from prehistoric Scotland and eight from northern England: 22 from the BA LoN in Westray, Orkney, dating to ∼1400 to 1700 BC (LoN); three from the IA KoS in Westray, Orkney, dating to the first two centuries AD; one from IA Milla Skerra (MS), Unst, Shetland; one from IA High Pasture Cave (HPC), Isle of Skye in the Hebrides (33);one from Neolithic Strath Glebe (SG), also Skye; a Pictish sample from Rosemarkie Cave (RC), Black Isle in northern Scotland, dating to 430 to 630 AD; a Beaker burial sample from Low Hauxley (LH),Northumberland; three BA samples from West Heslerton (WH), North Yorkshire; two IA samples from Knapton Wold (KW), North Yorkshire;and two IA samples from Carsington Pasture Cave (CPC), Derby shire.Whole-genome coverage varied greatly from 0.0007× to 0.8207×. Weundertook genome-wide analysis on samples above 0.009×, with samples averaging 0.194×. All samples passed contamination tests (Table1, SIAppendix, Table S1, DatasetS1 A and B, and SIAppendix, Fig. S1). We analyzed these in the context of genome data from Early Neolithic Orkney (n = 21)(13, 32)and Neolithic, Chalcolithic (CA), and BA Europe and 1,856 new mitogenomes from modern Orkney (n = 1,356) and Shetland(n = 500) (DatasetsS1C and S2).



Genome-Wide Variation.

ADMIXTURE analysis (Fig.1A) showed that the samples from BA Orkney closely resembled other northern European BA people in their overall genome-wide profiles and were highly distinct from Neolithic Orkney samples, which resembled more our Neolithic sample from Skye and other British and Irish Neolithic samples. Neolithic samples all lacked the CHG (“Caucasus hunter-gatherer”) component (in blue)that most clearly signals admixture from Pontic-Caspian Steppe pastoralists (34).The CHG fraction in Orkney (both BA and IA) is somewhat higher (∼40%)than in other Scottish CA and EBA (Early Bronze Age) samples but within the wide range of values for England (Fig.1A and SIAppendix, Fig. S2A). Modern Orcadians have an even higher fraction of the CHG component, reflecting medieval Norse settlement, estimated from modern genome-wide surveys at ∼20 to 25%(35)and ∼25 to 30% of modern Y chromosomes (36, 37).Geographical and chronological trends are portrayed more clearly in the PCA (principal component analysis) (Fig.1B and SIAppendix, Fig. S3). LoN BA samples broadly clustered with northern and central European Bell Beaker, CA, and BA samples, and KoS IA samples fell within the same broad cluster.

The software qpAdm (38)summarizes f4-statistics (which are similar to D-statistics) in order to estimate the direction and magnitude of gene flow, or admixture, from one population to another.We modeled admixture fractions with qpAdm using the three major components demonstrated by ADMIXTURE; Steppe,“Anatolian Neolithic Farmer” (ANF), and “Western Hunter-Gatherer” (WHG) (SIAppendix, Fig. S6 and DatasetS1F). The LoN comprised ∼55% of their ancestry from the Steppe, 33% from ANF, and 12% from WHG, broadly similar to published BA samples from across Britain (13).The populations that contributed to the LoN population were likely admixtures of those three components. To identify more proximal sources for the LoN, we modeled various potential Early Neolithic versus Late Neolithic/EBA source populations (Table2). The Orcadian BA samples could be plausibly modeled as ∼4 to7% local Neolithic and ∼93 to 96% Scottish BBC populations, but also as 1 to 5% local Neolithic and ∼95 to 99% French BBC populations or ∼1% local Neolithic and ∼99% Danish BA populations. Despite the uncertainty indicated by the SEs, these results clearly imply very high levels of replacement of the Neolithic people by people related to continental BBC immigrants by the EBA, with only ∼5% assimilation at most of the local autosomal gene pool. However, by the time the descendants of the BBC immigrants reached Orkney, they appear to have lost their Beaker cultural affiliation, as reflected in the dearth of Beaker-associated material culture in Orkney (6).


This predominance of I2a1b-M423 is surprising because it is completely absent elsewhere in CA/BA Europe, where the Y-DNA landscape is heavily dominated by R1b-M269 (Figs.24and SIAppendix, Figs. S13–S15).For example, in a dataset of 21 BBC males from Britain, 20 carry the R1b-M269 lineage and only one I2a, which is on the distinct I2a2a-M223 lineage. If we include CA and EBA Britain and Ireland, 41 out of 43 males carried R1b-M269, two I2a2a-M223, and none I2a1b-M423.
 
Well, I suppose it's to be expected that islands would experience founder effect and genetic drift.

For once farmer male lineages got lucky.
 
Lucky? Maybe not only.
The Neol people there were good builders, with perhaps, links with Atlantic and even farther links with Mediterranea. Someones with Long Barrows? I suppose they had skills for the life in this natural environment.
I have allways been amazed by this LN culture, spite I know little.
 
I'm not sure what happened. If Skarra Brae is any indication, their settlements were abandoned right around the time the climate changed, becoming much colder and wetter, and when the newcomers were arriving in the British Isles: 2500 B.C.E.

Nor does their knowledge seem to have been passed down, at least not indoor toilets and drainage systems, that's for sure, or even their skill in building in stone.

It's all rather sad, and a salutary lesson, I suppose: A culture can thrive for 600 years, and then disappear in the course of a generation.

 
From Wade Kotter in the I-M223 Y-DNA Haplogroup Activity Feed:

Eight of the nine male Bronze Age samples belong to the I-M423 branch, one step down from I-P37; the other belongs to R-M269. So it was the Neolithic I-P37 lineages that apparently survived in Bronze Age Orkney, but this evidence comes from only one location. All nine samples came from burials in a cemetery associated with a Bronze Age settlement at the site known as Links of Noltland [this comes from the name of a nearby golf course] on the Isle of Westray, the most northwesterly island in the Orkney archipelago. The settlement is dated from approximately 2500 to 1500 CAL BCE, and there are also ruins from the Neolithic Period in the same area.

https://www.familytreedna.com/groups/m223-y-clan/activity-feed

An ancient I-L126 sample (I2655, 3311ybp/1311bce) was found at Pabay Mor, Lewis, Western Isles, Scotland:

https://haplotree.info/maps/ancient...=Country&searchfor=Great Britain&ybp=500000,0

I agree with the notion of a bottleneck/founders effect followed by a sudden expansion impacting the I-L126 (3 branches)...S7753 (2 branches) > Y4142 (3 branches) > Y4751 (18 branches) line (FTDNA Haplotree). YFull TMRCA estimates: Y4142 (1600ybp/400ce) and Y4751 (1550ybp/450ce). What happened between 400ce and 450ce? The Romans abandoned Hadrian's Wall and evacuated Britain (420ce). Y4751 lineages likely expanded south, at least as far as the Midlands/Yorkshire, to judge from my "Norman" Emerson, Timmons, and Weatherill/Weatherhead Big Y matches at FT228503, with Weatherhead born in 1592 in Skipton, Yorkshire, where a Norman castle was located).
 
An article on the importation of "admixed" wives from the continent.

https://www.haaretz.com/archaeology...e-population-of-prehistoric-orkney-1.10706670

"The key point is that eight of the nine males were of a single male lineage that originated in the Neolithic Orkney population a thousand years earlier; yet the Links of Noltland population as a whole was akin to Northern European people in the Bronze Age. The Noltland people of the Bronze Age were not the same as the original Neolithic populations (from whom the men were descended).

The implication is that in northern Scotland, the men stayed put from the Neolithic onward and they married women coming from elsewhere. Marriage was patrilineal with house and rights passing through the male line. The incomers to Orkney were mainly women hailing, apparently, from the Scottish mainland, who were – by that time – not of aboriginal, but of continental descent, Wilson explains."
 
An article on the importation of "admixed" wives from the continent.

https://www.haaretz.com/archaeology...e-population-of-prehistoric-orkney-1.10706670

"The key point is that eight of the nine males were of a single male lineage that originated in the Neolithic Orkney population a thousand years earlier; yet the Links of Noltland population as a whole was akin to Northern European people in the Bronze Age. The Noltland people of the Bronze Age were not the same as the original Neolithic populations (from whom the men were descended).

The implication is that in northern Scotland, the men stayed put from the Neolithic onward and they married women coming from elsewhere. Marriage was patrilineal with house and rights passing through the male line. The incomers to Orkney were mainly women hailing, apparently, from the Scottish mainland, who were – by that time – not of aboriginal, but of continental descent, Wilson explains."

What "continental"? Continental Europe or rather Britain (Great Island) considered as "continent" compared to the northern little islands?
 
What "continental"? Continental Europe or rather Britain (Great Island) considered as "continent" compared to the northern little islands?

As the quote says,

"The incomers to Orkney were mainly women hailing, apparently, from the Scottish mainland, who were – by that time – not of aboriginal, but of continental descent, Wilson explains."
 
As the quote says,

"The incomers to Orkney were mainly women hailing, apparently, from the Scottish mainland, who were – by that time – not of aboriginal, but of continental descent, Wilson explains."

Thanks very much, Angela. I see I have to learn to read better!
 
Thanks very much, Angela. I see I have to learn to read better!

No problem, Moesan. Sometimes the eye just glides over a phrase without it registering.
 

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