Linkage Disequilibrium extension analysis on the Xq13 region in the island of Corsica

Genetic isolates represent exceptional resources in the identification of disease genes. In these populations the disease allele reveals Linkage Disequilibrium (LD) with markers over significant genetic intervals, therefore facilitating disease locus identification. In a previous study we examined the LD extension of the Xq13 region in three Corsican sub-populations from the inner mountainous region of the island and we have proposed a multistep procedure to carry out studies aimed to the identification of genes involved in complex diseases in Corsica. A prerequisite to carry out the proposed multistep procedure is the presence of a cline of LD in the island and a common genetic derivation of the different Corsican subpopulations. In the present paper we extended the analysis to the Corsican south/coastal population. The results obtained indicate a cline of LD on the island form the central mountainous toward the South central subpopulations. In addition the analysis of the DXS1225-DXS8082 haplotype revealed: 1) the derivation from a common genetic pool of the populations examined 2) a genetic peculiarity of the Corsican respect to the Europe.