Genetic studies in the Garfagnana population (Tuscany, Italy).

The relationship between geographic isolation and historical-demographic features and genetic structure and pattern of variation of genetic markers was analyzed in the population of Garfagnana, a semi-isolated mountainous area in the province of Lucca (Italy), taking into account hierarchical subdivisions. A random sample of unrelated individuals, whose parents were both born in this area, was typed for AB0, MN, Kell, Rh, AK, EsD, 6-PGD, AcP and ABH secretor status. The village samples were aggregated into larger population units: Two districts and six subdistricts. Comparisons were performed with population samples of the plain and the coastal area of the same province (Lucca). Phenotype and genetic differentiations among and within subdivisions were studied using G2, R statistic, Nei's method, Harpending & Ward's method and analysis of genetic distance and similarity matrices. The various parameters consistently show significant heterogeneity among the subdivisions, both at district and at subdistrict level. As expected, the gene diversity between and within subdivisions varies according to their distinctive features of isolation.