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May 17, 2017

The population genetic structure of Sicily and Greece

Filed under: Genetics,Italy,Mediterranean — Razib Khan @ 8:44 am


By total coincidence a paper came out yesterday, Ancient and recent admixture layers in Sicily and Southern Italy trace multiple migration routes along the Mediterranean (I blogged about the topic). It’s open access, and it has a lot of statistics and analyses. I’d recommend you read it yourself.

You see the Sicilian and Greek populations and their skew toward the eastern Mediterranean. But in the supplements they displayed some fineSTRUCTURE clustering, and at K = 3 you see that Europe and the Middle East diverge into three populations. What this is showing seems to be: 1) in red, those groups least impacted by post-Neolithic migration 2) in blue, Middle Eastern groups characterized by the fusion between western & eastern Middle Eastern farmer which occurred after the movement west of the ancestors of the “Early European Farmers” (who gave rise to the red cluster), who were related to the western Middle Eastern farmers 3) the groups most impacted by Pontic steppe migration.

The authors confirm what I reported over two years ago on this blog: mainland and island Greeks are genetically distinct, probably because the former have recent admixture from Slavs and Slav-influenced people. And, many Southern Italians resemble island Greeks.

One has to be careful about dates inferred from genetic patterns. For example:

Significant admixture events successfully dated by ALDER reveal that all Southern Italian and Balkan groups received contributions from populations bearing a Continental European ancestry between 3.0 and 1.5 kya

The beginning of folk wanderings in the Balkans which reshaped its ethnographic landscape really dates to the later 6th century, when the proto-Byzantines began to divert all its resources to the eastern front with Persia, and abandoned the hinterlands beyond the Mediterranean coast in Europe to shift its focus toward the Anatolian core of the empire. The Slavic migrations were such that there were tribes resident in the area of Sparta in the early medieval period. Presumably because they were not a seafaring folk they don’t seem to have had much impact on the islands.

Such an early period in the interval though can not be the Slavs. What can it be? I suspect that that there are signals of Indo-European migrations in there that are being conflated due to low power to detect them since they are rather modest in demographic impact. The islands such as Sardinia, Crete and Cyprus had non-Indo-European speakers down to the Classical period.

Overall it’s an interesting paper. But it needs a deeper dig than I have time right now.

September 12, 2012

A genetic map of Italy

Filed under: Anthroplogy,Genetics,Genomics,Italy — Razib Khan @ 9:44 pm

Since the Ralph & Coop paper on IBD patterns across Europe I’ve been keen to see what gets uncovered about Italy. Recall, if you will, that in that paper the authors noted that Italy in particular of European nations exhibits a lot of deep population structure. Whereas the network of descent ties together many European nations and regions, in Italy there are deep regional differences which seem to go back to antiquity. Additionally, more recently Sardinia has come under focus as possibly particularly informative in the ethnogenesis of European peoples. Until recently I was moderately skeptical of the utility of Sardinian samples in the HGDP data set. After all, it was an isolated island, and perhaps subject to peculiarities of low effective population size. Well, it turns out that it may be that modern Sardinians are the best approximation we have today to Southern Europeans ~5,000 years ago.

A new paper in PLoS ONE has a huge sample of Italians, and applies standard techniques to ascertain population structure. An Overview of the Genetic Structure within the Italian Population from Genome-Wide Data:

In spite of the common belief of Europe as reasonably homogeneous at genetic level, advances in high-throughput ...

June 2, 2011

Brown in Roma

Filed under: Identity,Italy — Razib Khan @ 10:43 pm

Bowlers and Batsmen Signal a Demographic Shift in an Eternal Cit:

The Catholic aid organization Caritas said there were 74,000 Bangladeshis legally residing in Italy, 75,000 Sri Lankans and about 65,000 Pakistanis. But experts estimate there are about 65,000 to 70,000 South Asians living here illegally. Many men work as waiters or run shops.

Just a note, I went to Italy last spring. South Asians were a pretty striking presence all around. There are Sri Lankans and Bangladeshis all around the Colosseum selling things. Bangladeshis were thick on the ground in Bologna too. Not so much in Genoa though. There it was Africans. A positive aspect highlighted in the article is that the non-Italians who come to Italy come to work. The Italians are frankly rather rude and racist compared to Fenno-Scandinavians, but the stereotype of a person of “immigrant background” isn’t a shiftless parasite as it is in parts of northern Europe.

Addendum: The main exceptions are the Gypsies, who tend to avoid conventional labor force activities. So they run what are obviously professional begging troupes in Florence.

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