Population Structure in the Mediterranean

A paper by Capelli et al. entitled "Population Structure in the Mediterranean Basin: A Y Chromosome Perspective" was published in March by the Annals of Human Genetics.

The authors identified four population clusters in the Mediterranean: North Africa, Arab, Central-East, and West. The Italian and Sicilian samples in the study fall into the Central-East Mediterranean cluster.

The conclusions are a little arcane, but the study found "limited genetic contribution of North African population" to the Italian and Sicilian samples, and also found that the Iberian (Spanish, French, etc) samples were distinct from those in the Central-East cluster. From page 217:

Of interest is the genetic separation that West Mediterranean samples from Iberia display vs. Central and East Mediterranean samples, as shown in this study by Y chromosome SNPs and STRs analyses and by autosomal data (Rosenberg et al. 2002). Investigation of the mtDNA distribution of genetic variation instead seems to support a more homogeneous situation for European Mediterranean populations. Higher female than male gene flow across populations and/or difference in population sizes of breeding individuals between the two genders have been suggested as possible explanations for this observation (Seielstad et al. 1998; Dupanloup et al. 2003).

The authors also concluded that a combination of Neolithic migration, Phoenician and Greek expansion, and Arab conquest played an important role in the genetic structure of the Central and Eastern Mediterranean basin.

Of course we know that genetic influences from more northern populations (Celts, Lombards, etc) are detectable as well, but examining that was beyond the scope of this particular study.