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2017 article claims: Nubians an admixed group with gene-flow from outside of Africa
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[QUOTE]Originally posted by the lioness,: [QB] Am J Hum Genet. 2004 Nov; 75[5]: 752–770. Published online 2004 Sep 27. doi: 10.1086/425161 PMCID: PMC1182106 [b]Ethiopian Mitochondrial DNA Heritage: Tracking Gene Flow Across and Around the Gate of Tears[/b] Toomas Kivisild, Haplogroup N Lineages in Ethiopians and Yemenis Lineages that belong to haplogroup N that cover virtually all mtDNA sequences in western Eurasia [Richards et al. 2000] show substantial frequencies both in the Yemeni [44%] and Ethiopian [31%] mtDNA pools. In this respect, Ethiopians differ explicitly from most other sub-Saharan African populations studied thus far. Within Ethiopia, the frequency of N lineages is significantly higher [P<.05] in samples that originate from its northern territory [48%], which was the center of the Aksum kingdom, than among other Ethiopians, mostly originating from the south-central part of the country [27%]. At the same time, there was no significant difference in the proportions of haplogroup N between the Semitic and Cushitic linguistic groups in our sample—for example, between Amharas and Oromos. Haplogroup [preHV]1 is by far the most frequent [10.4%] subclade in the Ethiopian N cluster [fig. 2B]. The majority of the Ethiopian [preHV]1 lineages match or derive from founder haplotypes common to Near Eastern, southern Caucasian, and North African populations [Krings et al. 1999; Metspalu et al. 1999; Richards et al. 2000; Kivisild et al. 2003b]. Previously, the highest frequency [20.4%] of [preHV]1 lineages was observed in Yemeni Jews [Richards et al. 2003], significantly higher than their frequency in our Yemeni non-Jewish sample [3.4%; P<.01]. This probably reflects strong genetic drift in the founding population of Yemeni Jews. Because [preHV]1 lineages occur in populations of the Near East, the Caucasus, and Mediterranean Europe—where African L0-L6 lineages are absent or rare—it is more likely that their presence in East Africa reflects a back-migration from the Near East rather than an in situ origin of [preHV]1 in Ethiopia [Richards et al. 2003]. Nevertheless, we notice that several Ethiopian [preHV]1 lineages, including [1] variants with a transversion at np 16305, [2] HVS-I motif 16126-16309-16362, and [3] HVS-I motif 16126-16172-16184A-16362, were not found in 185 [preHV]1 sequences sampled from >20,000 individuals from Arabia, the Near East, and Europe [Macaulay et al. 1999; Metspalu et al. 1999; Richards et al. 2000; authors' unpublished data], except for an HVS-I haplotype 16126-16305T-16362 that occurs [12.5%] in Ethiopian Jews [Thomas et al. 2002]. Their elevated frequency and uniform presence among major language groups in Ethiopia [table 1] suggests that these derived lineages may represent a relatively old introgression of lineages to the Ethiopian mtDNA pool from the Near East. Haplogroup HV1 is represented in Ethiopians by two different HVS-I motifs [fig. 2B]. The first of them, 16067-16274, observed in an Amharan mtDNA, has been reported in populations from the Arabian Peninsula [Di Rienzo and Wilson 1991; Richards et al. 2000], southern Egypt, and northern Sudan [Krings et al. 1999]. The other four sequences, present in Tigrais and Oromos, share a common HVS-I motif, 16067-16278-16362, that has not yet been reported in the literature. Two Yemeni HV* samples belong to a cluster of sequences with the characteristic 16220C transversion, observed more frequently in the Caucasus and the Near East [Richards et al. 2000]. When the fact that haplogroup H is the predominant subclade of N in most western Eurasian populations is considered, its frequency in Ethiopians is surprisingly low [0.7%]. Among the three haplogroup H lineages found, one Tigrai carried a characteristic HVS-I transition at np 16218, which has been observed in haplogroup H lineages—mostly in those of Near Eastern origin, but also in two Yemeni H sequences and two Assiut sequences from Egypt [Krings et al. 1999; Richards et al. 2000]. Three of the five haplogroup J lineages in Ethiopians share a distinct HVS-I motif, 16069-16126-16193-16300-16309 [J1c], that is characteristic of J sequences in populations from the southern Caucasus, the Near East, and North Africa [Di Rienzo and Wilson 1991; Richards et al. 2000; Brakez et al. 2001; Maca-Meyer et al. 2001; Plaza et al. 2003]. In East Africa, J1c sequences have been found in one Datoga from Tanzania [Knight et al. 2003] and in one Gurna from Egypt [Stevanovitch et al. 2004]. The other two Ethiopian J sequences, present in Tigrais, belonged to a subclade of J2 that is defined by a transition at np 6671 [Herrnstadt et al. 2002]. Most of the Yemeni J sequences, in contrast, share the combination of 16145 and 16261 mutations in haplogroup J1b, which is a common motif of J lineages in populations from the Near East and all over western Eurasia [Richards et al. 2000]. All Ethiopian and Yemeni haplogroup T sequences clustered with either T1 or T2 subclades, consistent with the classification of all existing European T coding-region sequences [Ingman et al. 2000; McMahon et al. 2000; Finnilä et al. 2001; Herrnstadt et al. 2002; Coble et al. 2004]. One Amhara T sequence, however, which harbors a transition at np 14233, characteristic of T2 sequences, lacked the other substitution at np 11812, present in all other Ethiopian and European T2 sequences. The np 11812 substitution was similarly absent in a complete North African T sequence [Maca-Meyer et al. 2001]. The Tigrai T1a sequence matches a Kerma sequence from Nubia [Krings et al. 1999], whereas the Amhara T1b sequence shows a mutation at np 16320 on top of the common founder haplotype in the Near East [Richards et al. 2000]. Five of the six T2 sequences detected among Amhara and Tigrai samples shared a transition at np 16292 that is widespread in the haplogroup T context in Europe, the Near East, and North Africa. However, the two Tigrai T2 sequences share a combination of four downstream HVS-I mutations [fig. 2B] that have not been reported elsewhere. N1a is a minor mtDNA haplogroup that has been observed at marginal frequencies in European, Near Eastern, and Indian populations [Mountain et al. 1995; Richards et al. 2000]. It occurs at a significant frequency in both Ethiopian and Yemeni populations. Six Ethiopian N1a lineages, restricted to Semitic-speaking subpopulations, show low haplotype diversity and include an exact HVS-I sequence match with a published N1a sequence from Egypt [Krings et al. 1999]. A related sequence, from southern Sudan [Krings et al. 1999], was misclassified as a member of the L1a clade [Salas et al. 2002]. Yemeni N1a sequences, on the other hand, display a high level of haplotype [h=0.89] and nucleotide [ρ=2.75±1] diversity, combined with the highest frequency [6.9%] of this haplogroup reported so far. Nevertheless, a clear asymmetry between E3b1-M78 and J1-M267 chromosomes is seen—the former are rare or absent in southern Arabia, whereas the latter are relatively frequent. Hence, Ethiopians may have been recipients of the southern Arabian J1-M267 chromosomes but have not been efficient donors of the E3b1-M78 chromosomes to southern Arabia, although East Africans may have carried the latter to Egypt and, farther, to Europe via the Levantine corridor. Furthermore, as already mentioned above, there is a profound difference in J1-M267 frequencies between the Semitic-speaking Amharas, who probably arrived relatively recently from Arabia, and the Cushitic-speaking Oromos, among whom the frequency of J1-M267 chromosomes does not exceed 3% [Cruciani et al. 2004]. Relevant data for other Ethiopian populations and Yemenis are desired for further exploration of this line of arguments. [/QB][/QUOTE]
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