Frequency distribution of mitochondrial DNA haplogroups in Corsica and Sardinia

Mitochondrial DNA (mtDNA) polymorphisms were analyzed by polymerase chain r eaction amplification and haplogroup-specific restriction screening in popu lations from Corsica and Sardinia. These included 56 individuals from the a rea of Corte, central Corsica (France), 51 individuals from Gallura, northe rn Sardinia (Italy), and 45 individuals from Barbagia, central Sardinia. Th e screening revealed that about 95% of mtDNAs could be grouped in 8 of the 9 European haplogroups, including H-K, T-V, and X. Our results confirmed th at these haplogroups encompass virtually all the mitochondrial lineages pre sent in Europe and can be detected in both northern and southern European p opulations. We also discovered 2 restriction sites (-73 Alw441 and +75 SphI ) that allow the detection of informative nucleotide changes in the second hypervariable segment of the control region, which help to detect the haplo group identity of mtDNAs without requiring further DNA sequencing. Haplogro up H was the most common mtDNA lineage in this sample, reaching frequencies from about 40% in Corsican and Gallurese populations, to about 65% in the Barbagian population. Haplogroup V, possibly originating in the Iberian pen insula, was found only in the central Sardinian sample. Of the 5 Corsican m tDNAs belonging to the haplogroup T, 4 had a restriction fragment length po lymorphism found only in this population. It seems that this mutation origi nated in Corsica and has had time to spread in the area, since the maternal grandmothers of the subjects came from different villages of the island, T he sample from central Sardinia shows a remarkable discontinuity with those from the northern part of the island and from Corsica. Gallura and Corsica seem to have undergone a more recent peopling event, possibly related to t he arrival of new mitochondrial variability from continental Italy, while B arbagia has apparently maintained more archaic haplotypes.