(Y chromosomal haplogroups)
A few weeks ago I saw the Y chromosomal haplogroup group distribution in Finland and Sweden. I’d know this disjunction for a while, but it really struck me. I got the numbers above from Eupedia, but you can find them elsewhere. Most of you probably know that Finland has a high fraction of N (they keep changing the nomenclature, so I’ll leave the number off). What’s curious to me is how low the fraction of N in the rest of Scandinavia is. Much of the N we see in Sweden may even be historical era migration of Finns into Sweden when the two nations were in political union (Finland was basically a Swedish colony). Another notable fact is that N is very common among Baltic people, whether Finnic in the language (Estonian) or Indo-European (Latvian and Lithuanian).
Another strange thing is that while the Indo-European lineages of R1 are both at very low frequency in Finland, I1, which is common to the west in Scandinavia, is not. The latest ancient DNA makes it clear that Finnic languages seem to have arrived in the Baltic in the period between 1000 and 500 BC. Before then Corded Ware/Battle Axe people seem to have been dominant in the East Baltic. These people usually carried Y chromosome R1a.
The fact that N is so high in the Baltic nations shows that newcomers arrived, and in the northern region language shifted happened, but in the south, it did not. Meanwhile, further north in Finland almost all the R1a lineages disappeared. Not so with I1. There are all sorts of tortured explanations for this pattern, so I won’t offer one.
Genome-wide the Finns aren’t that different. The largest proportion of their ancestry is still Yamnaya/steppe:
I only post this to illustrate how strong “male-mediated” dynamics can be. The proportion of Siberian ancestry in Finns is rather low, but > 50% of their Y chromosomes are N. I think it is plausible that one of the reasons for the massive reduction in R1 in Finland might be due to climate change and massive population collapse among the Battle Axe people of southern Finland, and the later arrival of Siberians.