Ethiopian mitochondrial DNA heritage: tracking gene flow across and around the gate of tears.

Approximately 10 miles separate the Horn of Africa from the Arabian Peninsula at Bab-el-Mandeb (the Gate of Tears). Both historic and archaeological evidence indicate tight cultural connections, over millennia, between these two regions. High-resolution phylogenetic analysis of 270 Ethiopian and 115 Yemeni mitochondrial DNAs was performed in a worldwide context, to explore gene flow across the Red and Arabian Seas. Nine distinct subclades, including three newly defined ones, were found to characterize entirely the variation of Ethiopian and Yemeni L3 lineages. Both Ethiopians and Yemenis contain an almost-equal proportion of Eurasian-specific M and N and African-specific lineages and therefore cluster together in a multidimensional scaling plot between Near Eastern and sub-Saharan African populations. Phylogeographic identification of potential founder haplotypes revealed that approximately one-half of haplogroup L0-L5 lineages in Yemenis have close or matching counterparts in southeastern Africans, compared with a minor share in Ethiopians. Newly defined clade L6, the most frequent haplogroup in Yemenis, showed no close matches among 3,000 African samples. These results highlight the complexity of Ethiopian and Yemeni genetic heritage and are consistent with the introduction of maternal lineages into the South Arabian gene pool from different source populations of East Africa. A high proportion of Ethiopian lineages, significantly more abundant in the northeast of that country, trace their western Eurasian origin in haplogroup N through assorted gene flow at different times and involving different source populations.

Disuniting uniformity: a pied cladistic canvas of mtDNA haplogroup H in Eurasia.

It has been often stated that the overall pattern of human maternal lineages in Europe is largely uniform. Yet this uniformity may also result from an insufficient depth and width of the phylogenetic analysis, in particular of the predominant western Eurasian haplogroup (Hg) H that comprises nearly a half of the European mitochondrial DNA (mtDNA) pool. Making use of the coding sequence information from 267 mtDNA Hg H sequences, we have analyzed 830 mtDNA genomes, from 11 European, Near and Middle Eastern, Central Asian, and Altaian populations. In addition to the seven previously specified subhaplogroups, we define fifteen novel subclades of Hg H present in the extant human populations of western Eurasia. The refinement of the phylogenetic resolution has allowed us to resolve a large number of homoplasies in phylogenetic trees of Hg H based on the first hypervariable segment (HVS-I) of mtDNA. As many as 50 out of 125 polymorphic positions in HVS-I were found to be mutated in more than one subcluster of Hg H. The phylogeographic analysis revealed that sub-Hgs H1*, H1b, H1f, H2a, H3, H6a, H6b, and H8 demonstrate distinct phylogeographic patterns. The monophyletic subhaplogroups of Hg H provide means for further progress in the understanding of the (pre)historic movements of women in Eurasia and for the understanding of the present-day genetic diversity of western Eurasians in general.

Origin and diffusion of mtDNA haplogroup X.

A maximum parsimony tree of 21 complete mitochondrial DNA (mtDNA) sequences belonging to haplogroup X and the survey of the haplogroup-associated polymorphisms in 13,589 mtDNAs from Eurasia and Africa revealed that haplogroup X is subdivided into two major branches, here defined as "X1" and "X2." The first is restricted to the populations of North and East Africa and the Near East, whereas X2 encompasses all X mtDNAs from Europe, western and Central Asia, Siberia, and the great majority of the Near East, as well as some North African samples. Subhaplogroup X1 diversity indicates an early coalescence time, whereas X2 has apparently undergone a more recent population expansion in Eurasia, most likely around or after the last glacial maximum. It is notable that X2 includes the two complete Native American X sequences that constitute the distinctive X2a clade, a clade that lacks close relatives in the entire Old World, including Siberia. The position of X2a in the phylogenetic tree suggests an early split from the other X2 clades, likely at the very beginning of their expansion and spread from the Near East.

Glucose-6-phosphate dehydrogenase (G6PD) mutations and UDP-glucuronosyltransferase promoter polymorphism among G6PD deficient Kuwaitis.

Screening of 1,080 Kuwaiti male blood donors for glucose-6-phosphate dehydrogenase (G6PD) deficiency revealed this condition in 70 (6.5%) individuals. Mutation analysis of all 70 G6PD deficient samples performed by PCR/RFLP and direct sequencing identified the 563C-->T (Mediterranean) in 72.9%, 202G-->A (A(-)) in 14.3%, 1003G-->A (Chatham) in 7.1%, and 143T-->C (Aures) in 1.4%. In 3 cases (4.3%) mutations remain unknown. Genotyping of all G6PD deficient samples for UDP-glucuronosyltransferase 1 (UDPGT1) gene promoter polymorphism revealed (ta)6/(ta)6 in 38.6%, (ta)7/(ta)7 in 15.7%, (ta)6/(ta)7 in 44.3%, and (ta)7/(ta)8 allele in 1.4% of cases. Thus, 4% of males in the Kuwaiti population have G6PD deficiency coexisting with low activity of the UDPGT1 promoter.