Biomedical subjects

Loredana Castrì

Publications and source records attributed to Loredana Castrì.

3 recordsLinked to original sources

PubMed2006

High resolution analysis and phylogenetic network construction using complete mtDNA sequences in sardinian genetic isolates.

For mitochondrial phylogenetic analysis, the best result comes from complete sequences. We therefore decided to sequence the entire mitochondrial DNA (mtDNA) (coding and D-loop regions) of 63 individuals selected in 3 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 3 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 with other European populations. We also identified in our samples a never previously described subhaplogroup, U5b3, which seems peculiar to the Ogliastra region.

DNA, Mitochondrial↗

PubMed2004

The Etruscans: a population-genetic study.

The origins of the Etruscans, a non-Indo-European population of preclassical Italy, are unclear. There is broad agreement that their culture developed locally, but the Etruscans' evolutionary and migrational relationships are largely unknown. In this study, we determined mitochondrial DNA sequences in multiple clones derived from bone samples of 80 Etruscans who lived between the 7th and the 3rd centuries b.c. In the first phase of the study, we eliminated all specimens for which any of nine tests for validation of ancient DNA data raised the suspicion that either degradation or contamination by modern DNA might have occurred. On the basis of data from the remaining 30 individuals, the Etruscans appeared as genetically variable as modern populations. No significant heterogeneity emerged among archaeological sites or time periods, suggesting that different Etruscan communities shared not only a culture but also a mitochondrial gene pool. Genetic distances and sequence comparisons show closer evolutionary relationships with the eastern Mediterranean shores for the Etruscans than for modern Italian populations. All mitochondrial lineages observed among the Etruscans appear typically European or West Asian, but only a few haplotypes were found to have an exact match in a modern mitochondrial database, raising new questions about the Etruscans' fate after their assimilation into the Roman state.

Bone and Bones↗

PubMed2002

Mitochondrial diversity in linguistic isolates of the Alps: a reappraisal.

In Stenico et al. (1996) we reported unusually high levels of mitochondrial diversity in the Alps. In particular, two communities of Ladin speakers appeared the most extreme European mitochondrial outliers at that time. Recently, it has been observed that some rare nucleotide substitutions occur repeatedly among those sequences, raising the possibility of systematic sequencing errors. No biological material was left from the previous study, and hence we had to sample new individuals from the same communities. Here, we present the HVSI sequence variation, along with haplogroup assignment based on restriction fragment length polymorphism (RFLP), in 20 Ladin speakers of Colle Santa Lucia. None of the new sequences displays substitutions at the sites viewed as problematic. However, Ladins still show high levels of mtDNA diversity, both within their community and with respect to other Europeans, and they can still be considered one of the main European mitochondrial outliers.

DNA, Mitochondrial↗