Both Mesolithic and Neolithic Britain male lineages belonged to haplogroup I

[Elizabeth]

I also saw this on another forum, about haplogroup I.



Another study published this year on the Neolithic in Britain found the same thing: the vast majority of both Mesolithic and Neolithic male lineages belonged to haplogroup I:

"We used Yleaf to determine Y-chromosome lineage labels in Mesolithic and Neolithic samples, requiring at least 1 read overlapping informative alleles and a concordance rate of 0.50. We found that the vast majority of Mesolithic and Neolithic individuals analysed belonged to haplogroup I, and more specifically to I2a2. This suggests that I2a2 Y-chromosome lineages were already present in Early Mesolithic Britain, and were either absorbed by incoming Neolithic populations or alternatively, these were assimilated in continental Europe and not in Britain, which could fit the small amount of British Mesolithic specific ancestry observed in agriculturalist groups from the region. We identify a single occurrence of haplogroup I2a1b in a sample from Kelco Cave, a lineage also identified in two Late Neolithic/Chalcolithic West Iberians.

The presence of I2a lineages in the British Neolithic mirrors previous findings obtained in a larger sample of British prehistoric human remains, where almost all Neolithic samples were determined to belong to this haplogroup and were later replaced by R1b-derived Copper/Late Bronze Age individuals with high levels of steppe-related ancestry. Our results suggest that despite the discontinuity observed between British Mesolithic and Neolithic samples at the autosomal and mitochondrial level, Y-chromosome lineage composition remained stable at the time of the appearance of agriculture in the region, with no evidence supporting the appearance of G2a-derived lineages characteristic of the Anatolian Neolithic."

'Ancient Genomes Indicate Population Replacement in Early Neolithic Britain' (S. Brace et al. 2019)

Supplementary material, section 2:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520225/

[alchemist223]

Surprised that Neolithic Britain had little G2a, as was common in the rest of Neolithic Europe. Any possible reasons for this discrepancy?

[Björnsson]

I also saw this on another forum, about haplogroup I.

I'm curious about K mtDNA in the context of I vs R. Although K is supposed to be Neolithic, it clusters with R, which may be a feature of the Polish Jewish population, but I am neither. Funny how the article goes on about Aegean and I'm 7.6%!


Western European and Scandinavian Mesolithic hunter-gatherers (WHGs & SHGs)Proto-Celts and Proto-Germans? Neolithic must be higher in the Channel Islands. The more things change, the more they stay the same...

[artemv]

Surprised that Neolithic Britain had little G2a, as was common in the rest of Neolithic Europe. Any possible reasons for this discrepancy?

In Middle Neolithic most of Europe had again I2a majority. Most groups on the continent, contemporary to arrival of first farmers to the British Islands were also mainly I2a. Thats true not just for megalith builders, also for Funnel Beaker. Early Neolithic LBK had G2a majority, but after likely violent collapse of LBK, later groups on former LBK territory were mostly I2a. At the momemt of Yamnaya-like people expansion only in Balkans and in Tripillia territory G2a were still a majority (we still do not know well about Appenines, there is a chance they still made majority there).

[glentane]

Surprised that Neolithic Britain had little G2a, as was common in the rest of Neolithic Europe. Any possible reasons for this discrepancy?
Agriculture/herding arrived comparatively late in the Isles. All sorts of guesses as to why. Large numbers of war-painted hostile bowmen, who would cheerfully scalp intruders with as much relish as they clubbed each other?
Or my favourite, the fact that even in the climatic optimum before the wetter and windier Sub-Atlantic phase, the weather was spectacularly foul, from a farmer's perspective.
Could also be a factor in why, for instance, the Cerny group hung on/acculturated to some extent in NW France.
Even today various UK agric. research establishments constantly trial shorter and shorter-stemmed cereal crops in an attempt to mitigate windthrow. Prehistoric barley/wheat was fairly long-stalked; good for thatch, bad for harvesting.
And then there's the constant, constant rain. I last saw widespread fungal damage in NE Scotland; rust, some nasty purple thing and I don't doubt ergot in 1984. Rain, fungus, storms which laid the crop, and then more rain, all the way to Christmas. Most folk just ploughed the rotten mess in, and "ate" the loss. A luxury that uninsured subsistence farmers do not enjoy. It's one reason novel rootcrops became so wildly popular up here, post-mediaeval.

And even today, nobody can outwit the sun. Old-school "bere" barley takes exactly one quarter-year to grow to some sort of harvestable form. Again, the most advanced local agronomists are still duelling/trialling over "plant early, risk the frost" vs. "plant late, risk still being green in autumn".

I suspect this is why the later neolithic Isles people had such an obsessive-compulsive interest in astronomy/cosmology. Hard to tell the time of day, or north from south, never mind the time of year when you only see the actual sun in winter for a few minutes at dawn and dusk, even in "good" weather before it hits the impenetrable cloud-base for the rest of the day.
Stars and planets in winter is a better bet, provided you can do the sums in your head, or using what might arguably be explained as large, ground-based circular slide-rules. Ceding enormous power from practical farmers, to those with the knowledge.
I can't remember whether it was Tacitus or Caesar (or somebody) who remarked on the habit of the island tribes of harvesting their "corn" green and either kilning it, or malting it, all the better to make ale, such was the risk even then of complete destruction of the crop by the ghastly climate.

tl;dr - late onset of farming in Isles, and the proximity to hypothesised HG/Farmer hybrid holdouts in NW Continent, suggests I-Yhg lineages may have been central to its establishment. Whether the Isles forager guys were originally related to their hipster cowboy cousins, trans-Manche ... well, we shall see, I hope.

[ibperry]

Surprised that Neolithic Britain had little G2a, as was common in the rest of Neolithic Europe. Any possible reasons for this discrepancy?

This article has some relevant background info:

https://genomicatlas.org/2021/04/15/bell-beakers-and-the-replacement-of-the-megalith-builders-in-western-europe/

It appears that many continental Western European Neolithic farmers were conquered by Hunter Gatherers prior to the movement of farmers into Britain, so British Hunter Gatherers were swamped by a population that was mixed and patrilineally disproportionately Western Hunter Gatherers and thus also haplogroup I like the Western Hunter Gatherers who were already in Britain. I am not sure how genetically distinct the conquering group of Western Hunter Gatherers on the continent would have been from those in Britain prior to having lots of kids with women from the conquered farmer population. The megalithic societies were, at least in many cases, not "pure" early European Farmer Societies but had been taken over by Western Hunter Gatherers, leading to predominantly WHG patrilineages but with autosomal dna still mostly EEF.