Elhassan Nuha, Gebremeskel Eyoab Iyasu, Elnour Mohamed Ali, Isabirye Dan, Okello John, Hussien Ayman, Kwiatksowski Dominic, Hirbo Jibril, Tishkoff Sara, Ibrahim Muntaser E
Department of Molecular Biology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan.
Department of Molecular Biology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan; Department of Biology, Eritrea Institute of Technology, Mai-Nefhi, Eritrea.
PLoS One. 2014 May 20;9(5):e97674. doi: 10.1371/journal.pone.0097674. eCollection 2014.
Human genetic variation particularly in Africa is still poorly understood. This is despite a consensus on the large African effective population size compared to populations from other continents. Based on sequencing of the mitochondrial Cytochrome C Oxidase subunit II (MT-CO2), and genome wide microsatellite data we observe evidence suggesting the effective size (Ne) of humans to be larger than the current estimates, with a foci of increased genetic diversity in east Africa, and a population size of east Africans being at least 2-6 fold larger than other populations. Both phylogenetic and network analysis indicate that east Africans possess more ancestral lineages in comparison to various continental populations placing them at the root of the human evolutionary tree. Our results also affirm east Africa as the likely spot from which migration towards Asia has taken place. The study reflects the spectacular level of sequence variation within east Africans in comparison to the global sample, and appeals for further studies that may contribute towards filling the existing gaps in the database. The implication of these data to current genomic research, as well as the need to carry out defined studies of human genetic variation that includes more African populations; particularly east Africans is paramount.
人类遗传变异，尤其是非洲地区的遗传变异，目前仍了解甚少。尽管与其他大陆的人群相比，非洲有效种群规模较大已成为共识，但情况依然如此。基于线粒体细胞色素C氧化酶亚基II（MT-CO2）的测序以及全基因组微卫星数据，我们观察到有证据表明，人类的有效种群规模大于目前的估计值，东非地区存在遗传多样性增加的集中区域，且东非人的种群规模至少比其他人群大2至6倍。系统发育分析和网络分析均表明，与各大洲的不同人群相比，东非人拥有更多的祖先谱系，这使他们处于人类进化树的根部位置。我们的研究结果还证实，东非可能是人类向亚洲迁徙的起点。该研究反映出，与全球样本相比，东非人群内部的序列变异程度惊人，并呼吁开展进一步研究，以填补数据库中现有的空白。这些数据对当前基因组研究的意义，以及开展涵盖更多非洲人群（尤其是东非人群）的人类遗传变异明确研究的必要性至关重要。
