All North Euros are significantly East Asian??

[joseph capelli]

I am not implying anything, I am stating facts.

[geomattica]

I am not implying anything, I am stating facts.

Ok, so is it a fact then that R1b's initial apearance in Europe is due to Neolithic or Calcolithic migrations? Or do you feel this is simply the most likely scenario.

[Hweinlant]

That's wishful thinking. HGDP Sardinian sample, which includes people from every region of Sardinia, did not show such high internal genetic diversity.

No, these Fst distances that you talk were based on y-dna not on autosomal.

High Differentiation among Eight Villages in a Secluded Area of Sardinia Revealed by Genome-Wide High Density SNPs Analysis

Giorgio Pistis et a 2009

We studied a particular area of Sardinia called Ogliastra, characterized by the presence of several distinct villages that display different history, immigration events and population size. Cultural and geographic isolation characterized the history of these communities. We determined LD parameters in 8 villages and defined population structure through high density SNPs (about 360 K) on 360 unrelated people (45 selected samples from each village). These isolates showed differences in LD values and LD map length. Five of these villages show high LD values probably due to their reduced population size and extreme isolation. High genetic differentiation among villages was detected. Moreover population structure analysis revealed a high correlation between genetic and geographic distances. Our study indicates that history, geography and biodemography have influenced the genetic features of Ogliastra communities producing differences in LD and population structure. All these data demonstrate that we can consider each village an isolate with specific characteristics.

About the FST figures between different European bio-regions:

The highest degree of differentiation has been detected between samples from Italy and Sweden (FST = 0.0060). This value is lower than the one detected between Baunei and Triei (FST = 0.0105), which are the least differentiated villages in this study.

Salmela et al. [72] analyzed the structure in various North Europe populations (Finland, Sweden, Northern Germany and Great Britain) and computed FST values in a subset of 6369 SNPs, finding values lower (from 0.0005 to 0.0072) than values observed among Ogliastra villages (0.0105 to 0.0324).

Summa summarum: Two Sardinian villages have HIGHER genetic differentation than Italian vs. Swedish average FSTs. This is sign of not "lot of admixture from various sources" but the exact opposite. Small breeding units, inbreeding and massive amount of genetic drift.

No wonder these people form their very own cluster in ADMIXTURE runs.

[joseph capelli]

Well N.Italians are genetically equidistant from Swedes and Sardinians. Other Italians are even further away. In the last centuries many people from the mainland have settled Sardinia (Sicilians, Venetians, Ligurians,...), so it's likely that some of those villagers are not Sardinian at all. This is from that link.

We studied a particular area of Sardinia called Ogliastra, characterized by the presence of several distinct villages that display different history, immigration events and population size. Cultural and geographic isolation characterized the history of these communities

[Motörhead Remember Me]

Sardinia ... Ogliastra, characterized by the presence of several distinct villages that display different history, immigration events

You write about migration from Venice, Sicily and Liguria that is recent and for sure a towns migration and not a migration to the mountains and rural areas of Sardinia. What is the specific regions migration and settlement history? Read about it so that we don't have to speculate.
The information in Wikipedia on Sardinia was this:

As time passed, the different Sardinian peoples appear to have become united in language[citation needed] and customs, yet remained divided politically as various small, tribal groupings, at times banding together, and at others waging war against each other.

On one mountain slope the people may have lived pretty isolated from the villagers on the opposite side of the peak. I'm sure the samples are from people who are Sardinians since forever and not people with roots in other Italian provinces.

Population is Ogliastra is very little, around 45000 people only, with some of the lowest densities in Italy. Dozens of minuscule villages spot the region of Ogliastra, each one with its tradition and its proud heritage.

Low population density is a sure recipe for isolation, just like in remote areas of Finland where we can also see extreme genetical distances becasue of drift.

The populations of the most isolated villages in Ogliastra are supplying pedigree, medical and genetic data to research in inherited diseases. This research is coordinated by the company SharDNA.

[joseph capelli]

I don't know the details of history of Sardinia. You should ask one of Sardinian members here.

[Hweinlant]

In the last centuries many people from the mainland have settled Sardinia (Sicilians, Venetians, Ligurians,...),

If they would have migrated to Sardinia en masse, it would actually bring down the FST difference contra rest of Europe. Two Sardinian villages having more than triple the FST difference between Eastern Finland and British isles really means something, and it doesnt imply intra-Italian migration waves, but very large scale isolation of Sardininian population.

Edit: If there would have large scale migration to Sardinian villages from Nigeria the FST figures would come explainable. I doubt there was Nigerian migration to Sardinia few generations ago.

[Jaska]

If they would have migrated to Sardinia en masse, it would actually bring down the FST difference contra rest of Europe. Two Sardinian villages having more than triple the FST difference between Eastern Finland and British isles really means something, and it doesnt imply intra-Italian migration waves, but very large scale isolation of Sardininian population.

Edit: If there would have large scale migration to Sardinian villages from Nigeria the FST figures would come explainable. I doubt there was Nigerian migration to Sardinia few generations ago.

Your source had a minor error:
"Salmela et al. [72] analyzed the structure in various North Europe populations (Finland, Sweden, Northern Germany and Great Britain) and computed FST values in a subset of 6369 SNPs, finding values lower (from 0.0005 to 0.0072) than values observed among Ogliastra villages (0.0105 to 0.0324)."

Actually 0.0072 is between East Finns and Swedes, while between East Finns and Brits it is 0.0096.

But still, those distances between Sardinian villages are huge. But here we have to remember the old genetic law, that we can observe greater genetic differences between very small units (villages) than between larger units (counties/regions). Similarly FST-distances between Icelanders were great, when they analyzed about 10 different regions.

If we take for example two families (one from Eastern Finland, another from Western Finland), differences are greater than between West Finns and East Finns in general. This is caused by the very method by which FST is calculated: the farther the "population" is from Hardy-Weinberg equilibrium, the greater the FST, so it takes the drift into account. And family or village is far more drifted than county or region, because county or region consists of many such small, differently drifted units, and therefore the average at the allele level is more neutral.

That is why we see greater differences between Sardinian villages than between the combined Sardinians and some other population.

[Flashrad]

Drift is to much of an issue in those admixture runs. That's why I prefer to use Y-DNA for getting more appropriate genetic distance results, when of course, the sample size is representative enough. For example, we all know that Y-DNA wise, Sardinian villages are all closely related and are not highly differentiated, thus indicating that they share most of their ancestors. Contrary to the common belief, autosomal DNA seems to be more susceptible to drift than uniparental markers. If you islolate two villages from a same popualtion with both an initial population of for example 500 individuals for a period of let's 500 years, I'm pretty much sure Y-DNA would end up less differentiated than autosomal DNA.

[Padre Organtino]

Drift is to much of an issue in those admixture runs. That's why I prefer to use Y-DNA for getting more appropriate genetic distance results, when of course, the sample size is representative enough. For example, we all know that Y-DNA wise, Sardinian villages are all closely related and are not highly differentiated, thus indicating that they share most of their ancestors. Contrary to the common belief, autosomal DNA seems to be more susceptible to drift than uniparental markers. If you islolate two villages from a same popualtion with both an initial population of for example 500 individuals for a period of let's 500 years, I'm pretty much sure Y-DNA would end up less differentiated than autosomal DNA.

A-DNA does way much better on a global scale due to the averaging out of drifts as explained by Jaska.