Periodically I get asked about Greek genetics. I check the literature, and it doesn’t seem like a deep survey has been performed on the modern populations yet. Yes, there are a few samples that the Estonian group has made public, but I don’t see an equivalent to the sort of stuff you see for Italy or Spain. Why? One speculation, which a Greek friend suggested wasn’t totally crazy, is that there may be nervousness if they found “too much” Northern European ancestry in northern Greece. In other words, Slavic ancestry.
The ancient DNA work shows that 2 to 3 thousand years ago the Hellenes weren’t more Northern European than they are now. But a big issue is there is as “Greek cline” in the modern populations. I have a lot of private samples I can’t ever share, but I can look at them. I have a bunch of individuals whose four grandparents were born in Greece, and some samples labeled from Thessaly. Check out the PCA, admixture, and a Treemix below.
I’ll let you draw your conclusions.
My neighbors the G*****ses hail from Sparta. They are fair and large, Sam was captain of the football team when we were in high school in a previous millennium.
OTOH, my doctor who’s family is from Thessaloniki, is small and compact.
South Slav and Anatolian Farmer would be my guesses.
The Byzantines resettled Greece with Anatolian peasants in the 8th and 9th centuries. That’s how the managed to rehellenize Greece which had been lost to Slavic migrants since the 6th centuries. If not for the Byzantine state, its possible that Greece would have become a Slavic speaking country with a Greek speaking minority(Sort of like Latin speaking minorities such as Vlachs in Yugoslavia and Bulgaria). Modern Greece, which looks to Ancient Greece for legitimacy should also celebrate its Byzantine history more often, which often is unfortunately ignored. You wouldn’t be here without them!
I’m curious – why does Dai seem to be the regular go-to as a proxy for East Asian admixture? Might not Koreans be a better proxy, especially if you’re looking for NE Asian admixture in particular? Dai should have some admixture from deeply diverged SE Asian populations; Mongolians and N Chinese have small but measurable West Eurasian admixture; but Koreans should be relatively pure in that sense, no?
For those who are interested in the genetic variation of Greeks (and also Turks), here are three PCAs using samples of Greeks and/or Turks collected in a way to represent the Greek or Turkish genetics of specific regions in SE Europe and northern West Asia. The first one focuses on both Greeks and Turks while the other two focus only on Greeks and do not use any Turkish sample.
https://drive.google.com/file/d/1bAbzpGy3khDesfR0mmAiGioFfRRZgAHB/view?usp=sharing (Greek and Turkish samples of Trabzon in East Pontus are so similar in genetics that their labels intersect)
https://drive.google.com/file/d/1YtAutgb3F2lPkzbU0qS0-GKhDo0CSxPF/view?usp=sharing
https://drive.google.com/file/d/1ENzZF_Duf2EvEIThhdxBjkhWNZ7Tlf8x/view?usp=sharing
For those who do not know, Rumeli and Deliorman are regions in the Balkans. The rest of the Turkish samples in my first PCA are from northern West Asia, primarily Anatolia. The places of origin of the Greek samples are straightforward from their labels.
@Marco, Razib can answer but generally I’d guess it’s that East Asians seem like a clade and Dai were sequenced for 1000Genomes, so have gold standard data for most purposes, so generally it seems like between the two that explains it. They’re not so diverged enough that using them as a reference would under-call it in most contexts by much, particularly using a qpAdm type approach. IDK though; someone could test this but the compression may not be that large. (Analogously, I don’t think using Sardinian to estate West Eurasian ancestry in South Asians is *that* underperforming, so you might trade off if they were present in higher quality samples etc).
I added the medieval Turkic ancient DNA samples that likely best represent the Turkic invaders of Anatolia and environs to my first PCA.
https://drive.google.com/file/d/1ckFGMIWT9u1ew1TaLiNwFvdrIVsVJMJH/view?usp=sharing
By the way, Cypriots are included in my first PCA too, but their label is not visible there due to intersecting with the labels of Central Anatolian and Cappadocian Greeks.