Modern studies of autosomal DNA rely on the study of large numbers of single-nucleotide polymorphisms (SNPs), i.e., of changes in a single letter of the genetic code. A recent study [3] used 10,000 such polymorphisms to investigate the genetic structure of European populations, including a sample of Greeks. Two different techniques were used: principal components analysis (PCA) , which find the most important dimensions summarizing the variability of the genetic data, and STRUCTURE a widely-used model-based clustering program, which assigns individuals to a number K of different clusters.
The results of the STRUCTURE runs are pictured below.
For each number of clusters (K), each cluster is assigned a color. Each individual from the studied populations corresponds to a vertical line, and consists in various proportions of the different clusters. We observe that the Greek individuals belong to the main European-West Asian-North African (Cluster) cluster for K up to 5. At K=6 a "Mediterranean" small cluster (green) emerges which encompasses particularly populations bordering the Mediterranean as well as Armenians. In particular, we observe that there is no visible contribution of the East Eurasian (Mongoloid) pink cluster or of Sub-Saharan African (Negroid) red cluster.
All the above from the most recent review ...
Greek autosomal DNA
by Dienekes Pontikos
Last Update: 5 Feb, 2009