Ana Teresa Fernandes

Y-chromosome Lineages from Portugal, Madeira and Açores Record Elements of Sephardim and Berber Ancestry

A total of 553 Y‐chromosomes were analyzed from mainland Portugal and the North Atlantic Archipelagos of Açores and Madeira, in order to characterize the genetic composition of their male gene pool. A large majority (78–83% of each population) of the male lineages could be classified as belonging to three basic Y chromosomal haplogroups, R1b, J, and E3b. While R1b, accounting for more than half of the lineages in any of the Portuguese sub‐populations, is a characteristic marker of many different West European populations, haplogroups J and E3b consist of lineages that are typical of the circum‐Mediterranean region or even East Africa. The highly diverse haplogroup E3b in Portuguese likely combines sub‐clades of distinct origins. The present composition of the Y chromosomes in Portugal in this haplogroup likely reflects a pre‐Arab component shared with North African populations or testifies, at least in part, to the influence of Sephardic Jews. In contrast to the marginally low sub‐Saharan African Y chromosome component in Portuguese, such lineages have been detected at a moderately high frequency in our previous survey of mtDNA from the same samples, indicating the presence of sex‐related gene flow, most likely mediated by the Atlantic slave trade.

Genetic profile of a multi-ethnic population from Guiné-Bissau (west African coast) using the new PowerPlex 16 System kit.

Allele and haplotype frequencies of 15 chromosome STR loci included in the kit PowerPlex16 System from Promega, were determined in a sample of unrelated males from Guiné-Bissau, a country from the west African coast. All individuals were subjected to an interview in order to make sure that their ancestors belonged to the same ethnic group. This way we intended to look for possible inter-ethnic differences. PowerPlex 16 includes STRs not studied before in any multi-ethnic population. The kit includes two new allele markers (Penta D and Penta E), which are very useful either in forensics or population genetic studies. The Guinean population presents significant differences when compared with other African populations.

Y-chromosome lineages in Cabo Verde Islands witness the diverse geographic origin of its first male settlers

The Y-chromosome haplogroup composition of the population of the Cabo Verde Archipelago was profiled by using 32 single-nucleotide polymorphism markers and compared with potential source populations from Iberia, west Africa, and the Middle East. According to the traditional view, the major proportion of the founding population of Cabo Verde was of west African ancestry with the addition of a minor fraction of male colonizers from Europe. Unexpectedly, more than half of the paternal lineages (53.5%) of Cabo Verdeans clustered in haplogroups I, J, K, and R1, which are characteristic of populations of Europe and the Middle East, while being absent in the probable west African source population of Guiné-Bissau. Moreover, a high frequency of J* lineages in Cabo Verdeans relates them more closely to populations of the Middle East and probably provides the first genetic evidence of the legacy of the Jews. In addition, the considerable proportion (20.5%) of E3b(xM81) lineages indicates a possible gene flow from the Middle East or northeast Africa, which, at least partly, could be ascribed to the Sephardic Jews. In contrast to the predominance of west African mitochondrial DNA haplotypes in their maternal gene pool, the major west African Y-chromosome lineage E3a was observed only at a frequency of 15.9%. Overall, these results indicate that gene flow from multiple sources and various sex-specific patterns have been important in the formation of the genomic diversity in the Cabo Verde islands.

Identification of new breakpoints in AZFb and AZFc

Microdeletions in AZFa, AZFb and AZFc regions lead to different patterns of male infertility, from severe oligozoospermia to non-obstructive azoospermia. Intrachromosomal homologous recombination mechanisms were already identified in patients with simultaneous microdeletions in the AZFb and AZFc regions. Ten patients with atypical AZFb and AZFc deletion patterns were studied. The definition of those microdeletions and the fine characterization of the respective breakpoints were performed using sequence tagged sites/single nucleotide variants-PCR and DNA sequencing. Y-chromosome haplogroups were determined to establish a putative association with the patterns obtained. Seven deletion patterns were identified, P5/terminal (30%; 3/10), P5/P1 distal (20%; 2/10), IR4/distal-P2, IR2/proximal-P1, IR4/distal-P1, P4/terminal and complete AZFb/c deletion (10%; 1/10). Breakpoint sequence analysis suggests that only in one patient the P5/P1 distal deletion pattern was due to a homologous recombination mechanism. Sequence alignment of the other deletion patterns suggest that they have resulted from non-homologous recombination mechanisms.

Genetic profile of the Açores Archipelago population using the new PowerPlex 16 system kit.

Allele and haplotype frequencies of 16 chromosome STR loci, 15 of them included in the Kit PowerPlex16 System from Promega were determined in a sample of unrelated males from the Açores Archipelago. All subjects were subjected to an interview in order to make sure that their ancestors belonged to the same island at least back to three generations. This way we intended to look for possible inter-islands differences. PowerPlex16 includes STRs not studied before in the Açores population. The Kit includes two new allele markers (Penta D and Penta E), which proved to be extremely useful for paternity testing (PD=0.921 and 0.971, respectively). The study revealed that the Açores population is considerable different from the previous studied Madeira population, but does not differ from that of the north Portugal. Nevertheless, some loci presented alleles not previously reported for Portugal.

Genetic differentiation of the Cabo Verde archipelago population analysed by STR polymorphisms

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.

Forensic analysis of dog (Canis lupus familiaris) mitochondrial DNA sequences: an inter-laboratory study of the GEP-ISFG working group.

A voluntary collaborative exercise aiming at the mitochondrial analysis of canine biological samples was carried out in 2006-2008 by the Non-Human Forensic Genetics Commission of the Spanish and Portuguese Working Group (GEP) of the International Society for Forensic Genetics (ISFG). The participating laboratories were asked to sequence two dog samples (one bloodstain and one hair sample) for the mitochondrial D-loop region comprised between positions 15,372 and 16,083 using suggested primers and PCR conditions, and to compare their results against a reference sequence. Twenty-one participating laboratories reported a total of 67.5% concordant results, 15% non-concordant results, and 17.5% no results. The hair sample analysis presented more difficulty to the participants than the bloodstain analysis, with a high percentage (29%) failing to obtain a result. The high level of participation showed the interest of the community in the analysis of dog forensic samples but the results reveal that crucial methodological issues need to be addressed and further training is required in order to respond proficiently to the demands of forensic casework.

Y-chromosome STR haplotypes in the Madeira archipelago population

Allele and haplotype frequencies of seven Y-chromosome STR loci were determined from a sample of 95 and 16 unrelated males from Madeira and Porto Santo Islands, respectively.

Y-chromosome STR haplotypes in the Açores Archipelago (Portugal).

Allele and haplotype frequencies of 10 Y-chromosome STR loci were co-amplified in a sample from the Açores Islands (Portugal). We found high haplotype diversity in the Açores sample (0.998). The genetic profile of this population revealed to be statistically different from that of Madeira Island and from North Portugal, two related populations with already a fairly amount of published data. This result stresses the importance of using local databases in forensic genetics.

Population data of five STRs in three regions from Portugal

Allele and haplotype frequencies of five chromosome STR loci (CD4, TPO, FES, TH01 and VWA) were determined for unrelated males throughout Portugal. This report presents STR data for three separate regions of Portugal, being the first time that data on the south of the country is presented. This study reveals that the three regions from Portugal are not genetically homogeneous. The north of Portugal presents significant differences in the CD4 locus, when compared with the other two populations. When compared with Madeira and Açores, the three regions show a different behavior at TPO and VWA loci.