Estudio Genético y Biodemográfico del archipiélago de las Azores (Portugal)

Abstract

The present thesis focuses on tow major areas: one centred on the biodemographic and genetic 8using mtDNA) characterization of the archipelago of the Azores, and the other focusing on the study of the own mitochondrial DNA (mtDNA). This last one, dealing specifically with in the development of a methodology to classify haplogrups and in the study of the mutation rate of the control region. The parameters considered to characterise, biodemographically and genetically this population, as well as to infer about the origin of its founders were: 1) The study of mtDNA of unrelated individuals with Azorean ancestry, from the 3 groups of islands: Eastern, Central and Western; 2) Characterization of the genetic structure of the island of Flores (Occidental group), from its discovery to present, using surnames; 3) Biodemographic characterization (endogamy, exogamy, migration and consanguinity) of the parishes of Flores (Occidental group), between the years of 1675 and 1875. The results obtained allowed to conclusions that: 1) The Azores present medium-high values of endogamy and consanguinity values similar to those observed in mainland Portugal and other south Europeans populations; 2) When considered as a all, the archipelago exhibits high degree of diversity, despite the significant differentiation of the Occidental group when compared to the other groups islands; 3) The strong population decrease that affected the archipelago and particularly the Flores island, have no major consequences on its genetic structure; 4) According to the phylogeographic analysis of mtDNA the majority of the lineages found in the Azores have their origins in European populations, primarily in mainland Portugal. There were also detected typical lineages from African and Near East populations. Based on the study of the mtDNA it was possible to develop a hierarchical methodology that allows the classification of DNAmt haplogroups in Caucasoid populations. The results obtained based on the study of the mtDNA in families allows to conclude that: 1) Heteroplamy must not be regard as an exceptional event, but as a very frequent phenomenon; 2) It is possible that mtDNA recombine; 3) There are no paternal contribution of mtDNA. 4) The value of the mutation rate for the D-loop is of 4.1878_10-6 mutations/pb/generation, a value that is in the upper end of that obtained using phylogenetic estimations.