Will Barrie

@Ycyfarwydd @TheAbyss369 I'm happy to have these discussions! Sorry if I was abrupt earlier - it's hard to communicate complex ideas on here. I disagree with you, but appreciate you bringing these ideas to wider audiences

@WilliamBarrie @TheAbyss369 You speak in too definite terms for something prehistoric you must account for some degree of error we can never be certain on these things with limited samples. You should adopt more of a way we speak in psych suggesting possibilities and being open to critique

Modern British people carry meaningful levels (~10%) of Western Hunter-Gatherer (WHG) ancestry — the Mesolithic foragers present before farming arrived. We can map which parts of their genome have been selectively retained or replaced. A 🧵:

@Ycyfarwydd @TheAbyss369 Okay I've watched. R1B is not hunter-gatherer, it is Steppe-associated. The southern Welsh show greater affinity to 'indigenous' Britons before Roman/A-S migrations (as you show in your video), but I am talking about much earlier ancestries/migrations here.

@WilliamBarrie @TheAbyss369 The video was one I made which was all about a research paper supporting my point if you bothered to look at it 🤣 I am yet to be proven wrong by anything you’ve said

@idrispukke_ Yep agreed, I haven't disagreed with that anywhere

@WilliamBarrie The modern British don't derive their EEF (ANF + WHG) from British EEFs, but continental ones. Bell Beaker replaced the local farmers in the bronze age.

Last week I posted about the legacy of WHG ancestry in modern British genomes. But what about the Neolithic transition? We carry about 50% 'Anatolian farmer' ancestry, but it's not evenly distributed across the genome, and it tells an equally striking story. A 🧵:

@Ycyfarwydd @TheAbyss369 You haven't linked research, you've linked a tiktok video. I agree N vs S Wales is different, but not what you are claiming. E.g. look at the POBI study showing important differences. However, it's not what you are claiming.

@WilliamBarrie @TheAbyss369 Link me the research as I did in my response. The research they made this 90% claim on states inferences cannot be made for wales. When they do look into wales there are genetics differences between the north and south which deserve closer attention

@Miniacarje98627 Roughly 50% ancestry from Anglo-Saxons in E Anglia, decreasing west and north, vs ~50% from pre-Anglo-Saxon Iron Age British. But different studies have concluded slightly different amounts! See Gretzinger (2022)

@Ycyfarwydd @TheAbyss369 There are plenty of southern Welsh genomes in UKB and none of these show what you are claiming.

@WilliamBarrie @TheAbyss369 vm.tiktok.com/ZNR97Mav7/ the welsh have continuous dna with ancient Britons, 50% HG is not implausible when you consider how poorly south welsh populations have been represented in research which bases this 90% wipe out claim on. Silures were described exactly the same as WHG

@IUnwhen50613 @nrken19 Next week :)

@WilliamBarrie @nrken19 Do steppe next

NB: I put 'Anatolian farmer' ancestry in quote marks in my first tweet. The exact proportions are dependent on reference sample choice and methodology, and ancestry to some extent depends on what time depth you are talking about. So, take these proportions with a pinch of salt!

Diet, density, new diseases. The selective pressures visible in Farmer ancestry in modern genomes are consequences of the agricultural transition: a 6,000-year-old set of adaptations, still legible in British genomes today. /end

Great new work from Alan Rogers that recapitulates the Cousins / Ragsdale signal using Alan's legofit / sitepattern toolkit

Aysu Okbay and I are hiring a postdoc to study gene–environment interplay in health & social inequalities 🧬 You'll analyze large genomic datasets as part of a 3-node consortium with Uppsala & Oslo. Based at @amsterdamumc 🇳🇱 Apply by May 4 below, please RT for karma points👇🏽

@javier_maravall Thanks! It's an unpublished figure but data is from Barrie et al (2024) - chromopainting of UKB using aDNA ref pops to infer local ancestry.

@WilliamBarrie Nice figure! What's the source?

@DrCJ_Houldcroft Thanks Charlotte!

Fascinating thread from Will Barrie on the parts of our British genomes that come from our hunter-gatherer ancestors, and which parts come in from more recent farmers.

@DrCJ_Houldcroft Yeah it is. It's evidence of positive selection at this locus, on a 'WHG haplotype', but that doesn't mean the mutation was necessarily present in WHG (would need to look directly at the aDNA data). Seems like the literature on this is a bit contested.

@WilliamBarrie Is HFE also the hemochromatosis risk locus?