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- Hollfelder, Nina, et al.
(författare)
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Northeast African genomic variation shaped by the continuity of indigenous groups and Eurasian migrations
- 2017
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- Northeast Africa has a long history of human habitation, with fossil-finds from the earliest anatomically modern humans, and housing ancient civilizations. The region is also the gate-way out of Africa, as well as a portal for migration into Africa from Eurasia via the Middle East and the Arabian Peninsula. We investigate the population history of northeast Africa by genotyping ~3.9 million SNPs in 221 individuals from 18 populations sampled in Sudan and South Sudan and combine this data with published genome-wide data from surrounding areas. We find a strong genetic divide between the populations from the northeastern parts of the region (Nubians, central Arab populations, and the Beja) and populations towards the west and south (Nilotes, Darfur and Kordofan populations). This differentiation is mainly caused by a large Eurasian ancestry component of the northeast populations likely driven by migration of Middle Eastern groups followed by admixture that affected the local populations in a north-to-south succession of events. Genetic evidence points to an early admixture event in the Nubians, concurrent with historical contact between North Sudanese and Arab groups. We estimate the admixture in current-day Sudanese Arab populations to about 700 years ago, coinciding with the fall of Dongola in 1315/1316 AD, a wave of admixture that reached the Darfurian/Kordofanian populations some 400–200 years ago. In contrast to the northeastern populations, the current-day Nilotic populations from the south of the region display little or no admixture from Eurasian groups indicating long-term isolation and population continuity in these areas of northeast Africa.
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| 2. |
- Hollfelder, Nina, et al.
(författare)
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The Genetic Variation of Lactase Persistence Alleles in Sudan and South Sudan
- 2021
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Ingår i: Genome Biology and Evolution. - : Oxford University Press. - 1759-6653. ; 13:5
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Tidskriftsartikel (refereegranskat)abstract
- Lactase persistence (LP) is a well-studied example of a Mendelian trait under selection in some human groups due to gene-culture coevolution. We investigated the frequencies of genetic variants linked to LP in Sudanese and South Sudanese populations. These populations have diverse subsistence patterns, and some are dependent on milk to various extents, not only from cows but also from other livestock such as camels and goats. We sequenced a 316-bp region involved in regulating the expression of the LCT gene on chromosome 2, which encompasses five polymorphisms that have been associated with LP. Pastoralist populations showed a higher frequency of LP-associated alleles compared with nonpastoralist groups, hinting at positive selection also among northeast African pastoralists. Among the LP variants, the -14009:G variant occurs at the highest frequency among the investigated populations, followed by the -13915:G variant, which is likely of Middle Eastern origin, consistent with Middle Eastern gene flow to the Sudanese populations. There was no incidence of the “East African” LP allele (-14010:C) in the Sudanese and South Sudanese groups, and only one heterozygous individual for the “European” LP allele (-13910:T), suggesting limited recent admixture from these geographic regions. The Beja population of the Beni Amer show three different LP variants at substantial and similar levels, resulting in one of the greatest aggregation of LP variants among all populations across the world.
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