Population structure in Sardinia on the basis of quantitative palmar dermatoglyphic traits

Abstract

We describe the genetic structure of twenty Sardinian subpopulations using quantitative palmar dermatoglyphic traits (a-b, and A-d counts, atd angle value, coefficient of Turpin and Lejeune, main line index, mean of A-, B-, C, and D-line terminations) of 3777 subjects (2043 males and 1734 females). The twenty subdivisions represent sixteen historical-geographic areas of the island in which people speaks Sardinian language, Sassarese and Gallura areas in which people speaks two Italian dialects, and the two communities of Alghero (Catalan speaking) and Carloforte (Ligurian speaking). Analysis was carried out for both hands and both sexes combined and using R-matrix technique and the extension of the Harpending-Ward model to quantitative traits according to Relethford & Blangero (1990). Multivariate minimum Fst value (0.0127) is higher than that of most. Mediterranean populations and shows the importance of isolation and genetic drift as evolutive forces at the basis of microdifferentiation among the Sardinian subpopulations considered. However, when the four populations not speaking Sardinian language are removed from the analysis, the value of Fst decreases to 0.008. The regression of mean genetic variance on distances from the centroid (rii values) states the marked effect of the genetic drift for Nuorese and Barbagia di Ollolai subdivisions (placed in the inner and mountainous areas of Sardinia) and reveals considerable levels of admixture for Carloforte subdivision. The contemporary genetic structure of these groups reflects their historical, linguistic and geographic characteristics. On the whole, our analysis confirms the usefulness of quantitative dermatoglyphic traits in studying genetic population structure.