August 17, 2006

mtDNA of Sardinian genetic isolates

Molecular Biology and Evolution, doi:10.1093/molbev/msl084

High Resolution Analysis and Phylogenetic Network Construction Using Complete mtDNA Sequences in Sardinian Genetic Isolates

Cristina Fraumene et al.


For mitochondrial phylogenetic analysis, the best result comes from complete sequences. We therefore decided to sequenced the entire mtDNA (coding and D-loop regions) of 63 individuals selected in three small Ogliastra villages, an isolated area of eastern Sardinia: Talana, Urzulei and Perdasdefogu. We studied at least one individual for each of the most frequent maternal genealogical lineages belonging to haplogroups H, V, J, K, T, U and X. We found in our 63 samples, 172 and 69 sequence changes in the coding and in the D-loop region respectively. Thirteen out of 172 sequence changes in the coding region are novel. It is our hypothesis that some of them are characteristic of the Ogliastra region and/or Sardinia.

We reconstructed the phylogenetic network of the 63 complete mtDNA sequences for the three villages. We also drew a network including a large number of European sequences and calculated various indices of genetic diversity in Ogliastra. It appears that these small populations remained extremely isolated and genetically differentiated compared to other European populations. We also identified in our samples a never previously described subhaplogroup, U5b3, that seems peculiar to the Ogliastra region.


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