mtDNA Analysis of Nile River Valley Populations: A Genetic Corridor or a Barrier to Migration?

Abstract

To assess the extent to which the Nile River Valley has been a corridor for human migrations between Egypt and sub-Saharan Africa, we analyzed mtDNA variation in 224 individuals from various locations along the river. Sequences of the first hypervariable segment (HV1) of the mtDNA control region and a polymorphic HpaI site at position 3592 allowed us to designate each mtDNA as being of "northern" or "southern" affiliation. Proportions of northern and southern mtDNA differed significantly between Egypt, Nubia, and the southern Sudan. At slowly evolving sites within HV1, northern-mtDNA diversity was highest in Egypt and lowest in the southern Sudan, and southern-mtDNA diversity was highest in the southern Sudan and lowest in Egypt, indicating that migrations had occurred bidirectionally along the Nile River Valley. Egypt and Nubia have low and similar amounts of divergence for both mtDNA types, which is consistent with historical evidence for long-term interactions between Egypt and Nubia. Spatial autocorrelation analysis demonstrates a smooth gradient of decreasing genetic similarity of mtDNA types as geographic distance between sampling localities increases, strongly suggesting gene flow along the Nile, with no evident barriers. We conclude that these migrations probably occurred within the past few hundred to few thousand years and that the migration from north to south was either earlier or lesser in the extent of gene flow than the migration from south to north.

Human Y chromosome haplogroup R-V88: a paternal genetic record of early mid Holocene trans-Saharan connections and the spread of Chadic languages

“…However, genetic studies have been limited and mainly focused on uniparental markers and the role of the Nile basin as a corridor for human movements between northeastern and eastern Africa. [11][12][13][14] There have only been a few high-resolution analyses to date regarding the distribution of Y-specific haplogroups in the African continent. The emerging picture indicates a clear differentiation between central/western sub-Saharan and northern African populations.…”

Tracing European Founder Lineages in the Near Eastern mtDNA Pool

“…The lower Nile (Egypt and northern Sudan) was also included, since this region is often treated historically with the Near East and since the HVS-I sequence data show that a large proportion of typically Near Eastern mtDNAs have penetrated the Nile Valley, where they coexist with sub-Saharan African mtDNAs (Krings et al 1999). We sampled widely in the Near East, for several reasons.…”

“…The Near Eastern populations analyzed for sequence variation in HVS-I of the mtDNA control region were as follows: 80 Nubians and 67 Egyptians (Krings et al 1999 Rienzo and Wilson (1991); 45 Israeli Druze (Macaulay et al 1999); 218 Turks from Turkey, including 74 from the studies by Comas et al (1996) and Calafell et al (1996); 53 Kurds from eastern Turkey; 191 Armenians from Armenia; and 48 Azeris from Azerbaijan.…”

Mitochondrial DNA analysis reveals diverse histories of tribal populations from India

“…Populations from the Indian subcontinent were compared to worldwide populations from Africa (!Kung, 29 Dinka, 30 Turkana and Yoruba 31 ), Europe (Germans, 32 Bulgarians and Turks 33 ), Caucasus (Armenians, Azerbaijanians, Georgians and Kabardinians 34 ), central Asia (Kazakh, Kirghiz andA gene tree was computed using the neighbor-joining method, based on p-distances, as implemented in MEGA version 2.1 (Kumar et al 44 ). The tree was rooted using a Neanderthal HV1 sequence 45 and bootstrap analysis was carried out with 500 replications.…”