Y-chromosomal DNA Haplotypes Research Articles

North African Berber and Arab Influences in the Western Mediterranean Revealed by Y-Chromosome DNA Haplotypes

We have analyzed Y-chromosome diversity in the western Mediterranean area, examining p49a,f TaqI haplotype V and subhaplotypes Vb (Berber) and Va (Arab). A total of 2,196 unrelated DNA samples, belonging to 22 populations from North Africa and the southern Mediterranean coast of occidental Europe, have been typed. Subhaplotype Vb, predominant in a Berber population of Morocco (63.5%), was also found at high frequencies in southern Portugal (35.9%) and Andalusia (25.4%). The Arab subhaplotype Va, predominant in Algeria (53.9%) and Tunisia (50.6%), was also found at a relatively high frequency in Sicily (23.1%) and Naples (16.4%); its highest frequency in Iberia was in northern Portugal (22.8%) and Andalusia (15.5%). In Iberia there is a gradient of decreasing frequencies in latitude for both subhaplotypes Va and Vb, related to eight centuries of Muslim domination (8th to 15th centuries) in southern Iberia.

Y-chromosome DNA haplotypes in human samples from Bahia, Brazil

Background: The Y-chromosome polymorphisms have a great value to population genetic studies and evolutionary aspects since these markers show high levels of heterogeneity within and between populations, permitting the geographical distribution and ancestry of patrilineages to be evaluated. They complement the autosomal STRs and mtDNA matrilineage information. Y-linked STRs remain stable in given paternal lineages over many generations so they are useful for identification in forensic cases, namely in criminal stain with male/female contributions. Methods: In this study, we report Y-chromosome haplotypes in a population sample with 68 unrelated males blood donors from Bahia state (Northeastern Brazil). The Y-STRs (DYS19, DYS389 I/II, DYS390 and DYS393) were determined after PCR pentaplexing with an automatic ABI sequencer. Results: In the Bahia population, we observed 47 different Y-chromosome haplotypes, of which 37 Y-haplotypes were unique. Only two Y-types were present in more than two persons. The most significant values of gene diversity were found in the markers DYS390, DYS389 II and DYS19 in decreasing order. The haplotype diversity value of the population studied was of 96.62. Conclusion: Comparing this Brazilian population with other Brazilian, Portuguese and African populations, we observed that the Bahia population has a similar haplotype diversity value to other Brazilian and Portuguese populations.

Genetic substructure in South African Bantu-speakers: evidence from autosomal DNA and Y-chromosome studies.

The extent of genetic differentiation between seven South African Bantu-speaking groups (Zulu, Xhosa, Tsonga/Shangaan, Southern Sotho, Pedi, Tswana, and Venda) was assessed from coancestry coefficients (F(ST)) estimated from autosomal serogenetic, DNA, and Y-chromosome DNA haplotypes. The overall F(ST) obtained from the autosomal data was 0.002, and that from the Y chromosome data was 0.014. The genetic relationships between groups examined were inferred from their cluster affinities in phylogenetic trees constructed from the genetic distances between them. Both autosomal and Y-chromosome DNA studies reveal that 6 of the 7 South African Bantu-speaking groups cluster according to their linguistic groupings, the exception being the Tsonga, who do not cluster with other Nguni language speakers, but rather with the Venda who live close to them. This suggests that the invading Shangaan-speakers, whose Nguni language was adopted by the Tsonga, did not have a major effect on the Tsonga gene pool, and that gene flow from the Venda into the Tsonga may have been considerable. Genetic distances were found to correlate with geographic distances between the regions where each group's apparent population density is the highest. Linguistic distances were also found to correlate with genetic distances, but linguistic and geographic distances showed no correlation. Together, these results suggest that linguistic and some genetic differentiation took place before the groups (or their forerunners) reached their present-day locations, and that further genetic change occurred after their arrival.

Erratum to: Y-chromosomal DNA haplotypes in infertile European males carrying Y-microdeletions

Erratum to: Y-chromosomal DNA haplotypes in infertile European males carrying Y-microdeletions

Y-chromosomal DNA haplotype differences in control and infertile Italian subpopulations.

Y-chromosomal DNA haplotypes were determined in 74 infertile and 216 control Italian males using eight biallelic markers. A significant difference in haplotype frequency was found, but could be explained by the geographical origins of the samples. The Y chromosome is thus a sensitive marker for population substructuring and may be useful for determining whether two population samples come from a single population, for example in association studies.

A selective difference between human Y-chromosomal DNA haplotypes.

DNA analysis is making a valuable contribution to the understanding of human evolution [1]. Much attention has focused on mitochondrial DNA (mtDNA) [2] and the Y chromosome [3] [4], both of which escape recombination and so provide information on maternal and paternal lineages, respectively. It is often assumed that the polymorphisms observed at loci on mtDNA and the Y chromosome are selectively neutral and, therefore, that existing patterns of molecular variation can be used to deduce the histories of populations in terms of drift, population movements, and cultural practices. The coalescence of the molecular phylogenies of mtDNA and the Y chromosome to recent common ancestors in Africa [5] [6], for example, has been taken to reflect a recent origin of modern human populations in Africa. An alternative explanation, though, could be the recent selective spread of mtDNA and Y chromosome haplotypes from Africa in a population with a more complex history [7]. It is therefore important to establish whether there are selective differences between classes (haplotypes) of mtDNA and Y chromosomes and, if so, whether these differences could have been sufficient to influence the distributions of haplotypes in existing populations. A precedent for this hypothesis has been established for mtDNA in that one mtDNA background increases susceptibility to Leber hereditary optic neuropathy [8]. Although studies of nucleotide diversity in global samples of Y chromosomes have suggested an absence of recent selective sweeps or bottlenecks [9], selection may, in principle, be very important for the Y chromosome because it carries several loci affecting male fertility [10] [11] and as many as 5% of males are infertile [11] [12]. Here, we show that one class of infertile males, PRKX/PRKY translocation XX males, arises predominantly on a particular Y haplotypic background. Selection is, therefore, acting on Y haplotype distributions in the population.

Jefferson fathered slave's last child.

There is a long-standing historical controversy over the question of US President Thomas Jefferson's paternity of the children of Sally Hemings, one of his slaves1,4. To throw some scientific light on the dispute, we have compared Y-chromosomal DNA haplotypes from male-line descendants of Field Jefferson, a paternal uncle of Thomas Jefferson, with those of male-line descendants of Thomas Woodson, Sally Hemings' putative first son, and of Eston Hemings Jefferson, her last son. The molecular findings fail to support the belief that Thomas Jefferson was Thomas Woodson's father, but provide evidence that he was the biological father of Eston Hemings Jefferson.

Y-chromosome DNA haplotypes in Basques

One Y-specific DNA polymorphism (p49/ TaqI) was studied in a sample of 97 French Basques and compared with those found in 7 other French, Iberian, and Italian populations. A particularly high frequency (72.2%) of Y-haplotype XV was observed in Basques, compared to values (mean of 41%) obtained in other Western Europeans. Basques were also characterized by virtual absence, or presence at a low level, of the South or Near Eastern haplotypes XII, VII, and VIII. Considered together, these results confirm that Basques are a very ancient European population which has had little previous contact with the Neolithics.

Y-Chromosome DNA Haplotypes in Basques

Y-Chromosome DNA Haplotypes in Basques