Sunday, November 28, 2010

Clusters galore with Dodecad populations

Number of individuals assigned to each cluster can be found in the spreadsheet. Populations in italics are composed entirely from Dodecad Project members.

Please read the post in Dienekes' Anthropology Blog to see what this type of analysis means.

47 MDS dimensions were retained, and the optimal number of clusters was 35. Retaining less or more dimensions may alter this number, as after a certain point extra dimensions only contribute noise to the analysis; this is a matter of investigation.

It is hardly practical to comment on all 35 clusters, so I will limit myself to a few observations:
  • Turks, Armenians, and Assyrians fall in cluster #1
  • Scandinavians, White Utahns, Germans, and some French fall in cluster #2
  • Portuguese, French, North Italians, Tuscans, Spaniards, and Romanians fall in cluster #3
  • Greeks, South Italians/Sicilians, Cypriots, and Sephardic Jews from Bulgaria and Turkey fall in cluster #4 (but see note)
  • Finns fall in cluster #5
  • Almost all Ashkenazi Jews fall in #6
  • All Dodecad Project Russians, plus reference Lithuanians and Belorussians fall in #9
8 Greeks fall in cluster #4 and 2 in cluster #3. However, many of the ones who fall in #4 also have some non-trivial probability of falling in #3. Probabilities for all other clusters are less than 0.1%. All Project Greeks can write to me to learn their exact probabilities.

Of course, it should be noted that:
  1. If two populations can be perfectly distinguished from each other, then there are genetic differences between them (they split from each other some time ago, they underwent different types of admixture, etc.) allowing the clustering algorithm to detect their differentiation
  2. If two populations cannot be distinguished from each other, this does not mean that they are not indistinguishable in principle; it does mean, however that through either common ancestry or very similar patterns of admixture, they have become quite similar to each other in the Eurasian context.
If you are a Dodecad Project member (23andMe data) from one of the populations in italics and are wondering which cluster you fall in, first check whether all individuals from your population fall in the same cluster, in which case you already know the answer.

Otherwise, you may write to me, with your DOD number, and I'll tell you.

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