Mitochondrial DNA geneflow indicates preferred usage of the Levant Corridor over the Horn of Africa passageway

J Hum Genet (2007) 52:436–447 DOI 10.1007/s10038-007-0132-7 ORIGINAL ARTICLE Mitochondrial DNA geneflow indicates preferred usage of the Levant Corridor over the Horn of Africa passageway D. J. Rowold Æ J. R. Luis Æ M. C. Terreros Æ Rene J. Herrera Received: 29 December 2006 / Accepted: 19 February 2007 / Published online: 20 April 2007
The Japan Society of Human Genetics and Springer 2007 Abstract Both the Levantine Corridor and the Horn of Africa route have figured prominently in early hominid migrations from Africa to Eurasia. To gauge the importance of these two African–Asian thoroughfares in the demic movements of modern man, we surveyed the mtDNA control region variation and coding polymorphisms of 739 individuals representing ten African and Middle Eastern populations. Two of these collections, Egypt and Yemen, are geographically close to the Levant and Horn of Africa, respectively. In this analysis, we uncover genetic evidence for the preferential use of the Levantine Corridor in the Upper Paleolithic to Neolithic dispersals of haplogroups H, J*, N1b, and T1, in contrast to an overwhelming preference in favor of the Horn of Africa for the intercontinental expansion of M1 during the Middle to Upper Paleolithic. Furthermore, we also observed a higher frequency of sub-Saharan mtDNA compared to NRY lineages in the Middle Eastern collections, a pattern also seen in previous studies. In short, the results of this Electronic supplementary material The online version of this article (doi:10.1007/s10038-007-0132-7) contains supplementary material that is available to authorized users. D. J. Rowold and J. R. Luis have contributed equally to this manuscript. D. J. Rowold
J. R. Luis
M. C. Terreros
R. J. Herrera (&) Department of Biological Sciences, Florida International University, University Park, OE 304, Miami, FL 33199, USA e-mail: J. R. Luis Departamento de Xenetica, Bioquimica e Inmunoloxia, Facultade de Bioloxia, Universidade de Vigo, Galicia, Spain 123 study suggest that several migratory episodes of maternal lineages occurred across the African–Asian corridors since the first African exodus of modern Homo sapiens sapiens. Keywords Mitochondrial DNA
NRY lineages
Human phylogeny
Middle East
Africa Introduction Modern human’s first Eurasian point of entry from Africa (54±8 kyr as estimated by Forster 2004) is believed by many to be at the far southwestern point of the Arabian Peninsula, located in present-day Yemen (Lahr and Foley 1994; Oppenheimer 2003; Forster 2004). This initial Red Sea crossing through the Bab el Mandab Strait or Cape of Sorrow (referred to as the Horn of Africa from this point forward) was most likely facilitated by several factors, including the shorter distance between the African and Arabian land masses (17 km vs. the 18 km observed today) as well as the much lower sea level during this time interval (80–60 m lower than that of present day) (Forster 2004; Siddall et al. 2003). However, the question remains concerning the relative roles played by the Horn of Africa passage and the Levantine Corridor in subsequent forays out of Africa, or for that matter, the multiple pilgrimages back to the continental birth place of Homo sapiens sapiens. A previous analysis (Luis et al. 2004) examining point and length polymorphisms in the non-recombining portion of the Y chromosome (NRY) revealed a marked asymmetry regarding the use of these two inter-continental corridors. The results of the study indicated that since the last glacial maximum (LGM) [25–15 kyr according to Fagan (1990)], the Levant was a major thoroughfare used in the spread of J Hum Genet (2007) 52:436–447 NRY markers E3b1-M78 and E3b3-M123 into Eurasia as well as the North African dissemination of K-M70 and R1*-M173 in the Upper Paleolithic (40–10 kyr) and GM201, J-p12f2, R1a1-M17 and R1b3-269 during the Neolithic. In contrast, there is very little evidence of a Eurasian dispersal of NRY haplogroups via the Horn of Africa during these times. Furthermore, it was observed that the more recent arrival of the derivative M173 haplogroups into North Africa also occurred by way of the Levantine Corridor whereas the Bantu marker, M2, dispersed into Arabia and Asia via the East African slave trade routes during the last millennium. The main objective of the current study is to assess the relative importance of the Levantine Corridor and the Horn of Africa as genetic conduits by using phylogeographic patterns of mitochondrial DNA (mtDNA) variation. To investigate which (if any) of these two pathways was favored in the dispersal of maternal lineages via African– Asian migrations during the Middle Paleolithic to Neolithic, we examine mtDNA HVI and HVII sequence motifs, coding-sequence polymorphisms, and the haplogroup frequency distribution of six Middle East populations. These collections comprise those representing the Levantine Corridor (Egypt and Jordan), and the Arabian Peninsula (Yemen, Oman, Qatar and United Arab Emirates or UAE for short). A second aim of this study is to track more recent gene flow of sub-Saharan individuals along the East African trade routes as well as across the Central African Corridor. To accomplish this objective, we examined four groups from sub-Saharan Africa (Benin, Cameroon, Rwanda, and Kenya). In addition, the mtDNA sampling along the Levantine Corridor and the Horn of Africa as well as the subSaharan corridors is enriched by the assessment of Middle Eastern and African HVI motifs compiled from the available literature. This supplementary data also provides a wider geographical context in which to interpret our results. 437 NIH guidelines as well as with any other additional regulations imposed by the institutions involved. In addition, mtDNA haplogroup and control region sequence information from 15 published Eurasian and African populations was used in further analysis (see Table 1). DNA extraction, PCR and sequencing Genomic DNA was isolated from the peripheral leukocyte fraction of whole blood as previously described (Antunez de Mayolo et al. 1999). Both the HVI and HVII regions were PCR-amplified using primers described by Stoneking et al. (1991). Fragments were sequenced with Big Dye v 1.1 from Applied Biosystems in accordance with the recommended protocol. Sequenced samples were cleaned with spin filters (Centri Sep96 from Princeton Separations) and run on a 3100 Genetic Analyzer from ABI. The resulting sample sequences were aligned and compared to the revised Cambridge Reference Sequence (rCRS) (Anderson et al. 1981; Andrews et al. 1999). Haplogroup assignment Haplogroup assignment followed the basic classification scheme of Macaulay et al. (1999). Additional reports (Salas et al. 2002; Kivisild et al. 2004; Quintana-Murci et al. 2004; Salas et al. 2004) were consulted as needed to further delineate the haplotypes and assign them geographical labels (Western Eurasian, Eastern Eurasian, South Asian, and African). Restriction (...truncated)