Story of Haplogroup G2a

We’re constantly writing and rewriting the human DNA story. I’m a member of yDNA Haplogroup G2a-L497. When I first started my yDNA journey in 2000, the testing companies were still using STRs only. When they started using SNPs, it wasn’t clear whether I would end up in haplogroup G or haplogroup I. Frankly, I was hoping for I because it was “Scandinavian”.

In the end, it turned out I am Haplogroup G, but even then the L497 SNP was a ways off in the future. There were discoveries, and more discoveries, and more. L42 and L43 were discovered by someone scouting my results at 23andme. Someone smart enough to realize they would turn out to be the defining SNP mutation for a large subgroup of G.

Then we went through the “story years”. Every online DNA group had people advocating different theories of Haplogroup G. It originated in the area north of Caucasus. When and how did it spread into Europe? Was it a marker for Indo-Europeans? Was it spread by Roman soldiers? By Jewish merchants? By barbarian invaders (most popularly the Alans)?

I suggested it was probably linked to the Rhaetians and Etruscans. Ray Banks, our expert, said I was I an idiot, then much later backed down but never did give me credit for being the one to suggest it originally. When I complained to him, his response was that he gets so many crackpot emails he can’t be expected to realize when one of them could be right. (I love that story.)

Throughout these story years, the actual experts were saying Haplogroup G probably came to Europe with the spread of farming during the Neolithic period. The other stories were only really possible because archaeologists (as opposed to geneticists) were entrenched in an ideology that there is something racist about attributing the spread culture to migrations. That idea held sway for a generation, but they were wrong about it.

We’re all looking for stories, I think. So many false starts to ours. I’ve had the impression for several years now that our Haplogroup G story is moving in a particular direction. Once upon a time we were probably one of the main haplogroups in Old Europe, probably predating the Indo-Europeans, and we probably retreated to mountainous areas (or maybe survived mainly in mountain areas) when Europe was overrun by the R1b people, who are now the majority in western Europe.

(I’ve had some push back because it seems to go against the romantic notion that our ancient ancestors preferred mountains and goat herding as a legacy of our origin in the Caucasus Mountains. My counter-argument has been that this goat herding story seems to be contrary to the idea that we came to Europe as Neolithic Farmers.)

Now I find the whole story nicely summarized by Maciamo Hay, Haplogroup G2a (Y-DNA), at Eupedia. He’s always good at getting across complex ideas and arguments in simple language.

Nowadays G2a is found mostly in mountainous regions of Europe, for example, in the Apennine mountains (15 to 25%) and Sardinia (12%) in Italy, Cantabria (10%) and Asturias (8%) in northern Spain, Austria (8%), Auvergne (8%) and Provence (7%) in south-east France, Switzerland (7.5%), the mountainous parts of Bohemia (5 to 10%), Romania (6.5%) and Greece (6.5%). The hilly terrain of southern Europe indeed makes it ideally suited for herding goats, which G2a men brought with them during the Early Neolithic period. But the most likely explanation is that mountains provided refuge for G2a tribes after the Proto-Indo-European speakers invaded Europe from the steppes of Russia and Ukraine during the Late Copper Age and the Bronze Age (see history of R1a and R1b).

If you look at the heat map I’ve attached here, you’ll see a concentration in Switzerland. That’s where our Hauris are from. Probably we’ve been there since the Bronze Age and perhaps since the Stone Age. And that’s the story of Haplogroup G2a in a nut shell.

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