Admixture facilitates genetic adaptations to high altitude in Tibet.
Admixture facilitates genetic adaptations to high altitude in Tibet.
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DOI：
10.1038/ncomms4281
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发表时间：
2014
影响因子：
16.6
通讯作者：
Di Rienzo A
中科院分区：
文献类型：
--
作者：
Jeong C;Alkorta-Aranburu G;Basnyat B;Neupane M;Witonsky DB;Pritchard JK;Beall CM;Di Rienzo A
混合被认为是人类群体的一个普遍特征，这重新燃起了人们对基因交换可以促进适应新环境的可能性的兴趣。对藏人的研究揭示了 EGLN1 和 EPAS1 基因的高海拔适应能力，与较低的血红蛋白浓度有关。然而，人们对这些变体或藏人的历史仍然知之甚少。在这里，我们分析了尼泊尔夏尔巴人的基因型数据，发现藏人是与夏尔巴人和汉人有关的祖先群体的混合体。 EGLN1和EPAS1基因显示西藏基因组中高海拔血统的显着富集，表明来自低海拔的移民从高地人那里获得了适应性等位基因。因此，夏尔巴人和藏人共享适应性血红蛋白特征。这种混合介导的适应与适应性基因渗入具有相同的重要特征。因此，我们发现了一种新的机制，超越了对新突变或长期变异的选择，通过该机制，种群可以适应当地环境。
Admixture is recognized as a widespread feature of human populations, renewing interest in the possibility that genetic exchange can facilitate adaptations to new environments. Studies of Tibetans revealed candidates for high-altitude adaptations in the EGLN1 and EPAS1 genes, associated with lower hemoglobin concentration. However, the history of these variants or that of Tibetans remains poorly understood. Here, we analyze genotype data for the Nepalese Sherpa, and find that Tibetans are a mixture of ancestral populations related to the Sherpa and Han Chinese. EGLN1 and EPAS1 genes show a striking enrichment of high-altitude ancestry in the Tibetan genome, indicating that migrants from low altitude acquired adaptive alleles from the highlanders. Accordingly, the Sherpa and Tibetans share adaptive hemoglobin traits. This admixture-mediated adaptation shares important features with adaptive introgression. Therefore, we identify a novel mechanism, beyond selection on new mutations or on standing variation, through which populations can adapt to local environments.