Browsing by Author "Fernandes, A. T."
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- Genetic differentiation of the Cabo Verde Archipelago population analysed by STR polymorphismsPublication . Fernandes, A. T.; Velosa, R.; Jesus, J.; Carracedo, A.; Brehm, A.Allele frequencies for 17 STR loci were analyzed in a sample of unrelated males from the Cabo Verde Archipelago. The samples were gathered in such a way that the origin of the subjects was perfectly identified, and they could be included in one of the leeward or windward groups of islands. This study reveals that there are significant differences between both groups of islands, and between Cabo Verdeans and other populations from sub-Sahara Africa including the Guineans, the most probable source population for Cabo Verdeans. This study confirms mtDNA data and, together with HLA and Y chromosome data already published, shows that the Cabo Verde population is sub structured and atypical, diverging substantially from mainland sub-Saharan populations. Overall these differences are most probably due to admixture between sub-Saharan slaves brought into the islands and other settlers of European origin. In the absence of a clear indication of a different ethnic composition of the first sub-Saharan settlers of Cabo Verde, the differentiation exhibited in both groups of islands can be most probably be attributed to genetic drift.
- The Y-chromosome short tandem repeats variation within haplogroup E3b: evidence of recurrent mutation in SNPPublication . Fernandes, A. T.; Rosa, A.; Gonçalves, R.; Jesus, José; Brehm, A.Haplogroup E3b is defined by a single nucleotide mutation (SNP) in locus M35 and is found at high fre quency (more than 35%) in populations from North Africa with a heterogeneous distribution. On the basis of compilation of 553 Y-chromosomes from Europe and 633 from sub-Saharan Africa we selected 130 individuals belonging to haplogroup E3b and characterized subhaplogroups according to the Y-Chromosome Consortium nomenclature. Y-chromosome haplo types can be defined using short tandem repeats (STR). The use of STRs makes it possible to measure diversity and esti mate age coalescence. Significant differences on frequencies of Y-chromosome STR loci were found among the E3b sub haplogroups and the same was observed when haplotype frequencies were considered. Some mutations in SNPs were detected when comparing E3b subhaplogroups with the correspondent STR haplotypes. These results show that the mutation rate for some SNPs could be higher than previously thought and also that it is important to associate both haplo type and haplogroup in Y-chromosome studies