Ethiopian Mitochondrial DNA Heritage: Tracking Gene Flow Across and Around the Gate of Tears

University of Calabar, Calabar, Cross River, Nigeria
The American Journal of Human Genetics (Impact Factor: 10.93). 12/2004; 75(5):752-70. DOI: 10.1086/425161
Source: PubMed


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.

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    • "Richards et al. (2003) and others (e.g., Kivisild et al., 2004; Cern y et al., 2008; Badro et al., 2013; Fernandes et al., 2015) suggest that Arab slave trade over the last 2,500 years resulted in significant female-mediated migration from sub-Saharan Africa to Yemen as evidenced by a high frequency (relative to other Near Eastern regions) of African L haplogroups. Specifically, analyses of mitochondrial hypervariable region (HVR) sequences suggest there has been ongoing migration between Yemen and the Horn-of-Africa over the last 3,000–4,000 years as well as broader migration into Yemen from sub-Saharan Africa, South Asia, and western Eurasia (Kivisild et al., 2004; Cern y et al., 2008). Furthermore, analyses using whole mitogenome sequences from haplogroups frequently found in Yemen (e.g., HV1, R0a, and R2) indicate Yemeni mitogenome variation may be the product of multiple population expansions within the last 10–15 kya ( Cern y et al., 2011; Musilov a et al., 2011; Al-Abri et al., 2012). "
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    ABSTRACT: Objectives: Anatomically, modern humans are thought to have migrated out of Africa ∼60,000 years ago in the first successful global dispersal. This initial migration may have passed through Yemen, a region that has experienced multiple migrations events with Africa and Eurasia throughout human history. We use Bayesian phylogenetics to determine how ancient and recent migrations have shaped Yemeni mitogenomic variation. Materials and methods: We sequenced 113 mitogenomes from multiple Yemeni regions with a focus on haplogroups M, N, and L3(xM,N) as these groups have the oldest evolutionary history outside of Africa. We performed Bayesian evolutionary analyses to generate time-measured phylogenies calibrated by Neanderthal and Denisovan mitogenomes in order to determine the age of Yemeni-specific clades. Results: As defined by Yemeni monophyly, Yemeni in situ evolution is limited to the Holocene or latest Pleistocene (ages of clades in subhaplogroups L3b1a1a, L3h2, L3x1, M1a1f, M1a5, N1a1a3, and N1a3 range from 2 to 14 kya) and is often situated within broader Horn of Africa/southern Arabia in situ evolution (L3h2, L3x1, M1a1f, M1a5, and N1a1a3 ages range from 7 to 29 kya). Five subhaplogroups show no monophyly and are candidates for Holocene migration into Yemen (L0a2a2a, L3d1a1a, L3i2, M1a1b, and N1b1a). Discussion: Yemeni mitogenomes are largely the product of Holocene migration, and subsequent in situ evolution, from Africa and western Eurasia. However, we hypothesize that recent population movements may obscure the genetic signature of more ancient migrations. Additional research, e.g., analyses of Yemeni nuclear genetic data, is needed to better reconstruct the complex population and migration histories associated with Out of Africa. Am J Phys Anthropol, 2015. © 2015 Wiley Periodicals, Inc.
    Full-text · Article · Nov 2015 · American Journal of Physical Anthropology
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    • "ble S1 ) . This is reflected in a sub - stantial Eurasian autosomal component in Eastern Africa , which is also evident to some extent in Kenya ( Pagani et al . 2012 ) . Due to deep ancestry and the distribution of these lineages ( Abu - Amero et al . 2008 ; Brakez et al . 2001 ; Černý et al . 2008 ; Coudray et al . 2009 ; Fernandes et al . 2012 ; Kivisild et al . 2004 ; Olivieri et al . 2006 ; Rhouda et al . 2009 ; Richards et al . 2000 , 2003 ) , none of the West Eurasian mtDNAs found in Uganda has a likely European source , for example , resulting from the heavy European colonial involvement since the 1870s ( Maxon 2009 ) . One possibility is a Bronze - Age dispersal from the Near East accompanying"
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    ABSTRACT: The Great Lakes lie within a region of East Africa with very high human genetic diversity, home of many ethno-linguistic groups usually assumed to be the product of a small number of major dispersals. However, our knowledge of these dispersals relies primarily on the inferences of historical, linguistics and oral traditions, with attempts to match up the archaeological evidence where possible. This is an obvious area to which archaeogenetics can contribute, yet Uganda, at the heart of these developments, has not been studied for mitochondrial DNA (mtDNA) variation. Here, we compare mtDNA lineages at this putative genetic crossroads across 409 representatives of the major language groups: Bantu speakers and Eastern and Western Nilotic speakers. We show that Uganda harbours one of the highest mtDNA diversities within and between linguistic groups, with the various groups significantly differentiated from each other. Despite an inferred linguistic origin in South Sudan, the data from the two Nilotic-speaking groups point to a much more complex history, involving not only possible dispersals from Sudan and the Horn but also large-scale assimilation of autochthonous lineages within East Africa and even Uganda itself. The Eastern Nilotic group also carries signals characteristic of West-Central Africa, primarily due to Bantu influence, whereas a much stronger signal in the Western Nilotic group suggests direct West-Central African ancestry. Bantu speakers share lineages with both Nilotic groups, and also harbour East African lineages not found in Western Nilotic speakers, likely due to assimilating indigenous populations since arriving in the region ~3000 years ago.
    Full-text · Article · Jul 2015 · Human Genetics
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    • "Interestingly, the flow of migrations from East Africa to the Arabian Peninsula seem to have been more recent, occurring mainly during the Arab-conducted slave trade initiated only in the seventh century AD (Richards et al., 2003; Kivisild et al., 2004). Curiously , Kivisild et al. (2004) detected a high proportion Fig. 3. Network for HVRI diversity in several regional populations. "

    Full-text · Dataset · Jan 2015
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