Andean, Tibetan, and Ethiopian patterns of adaptation to high-altitude hypoxia
Andean, Tibetan, and Ethiopian patterns of adaptation to high-altitude hypoxia
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DOI：
10.1093/icb/icj004
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发表时间：
2006-02-01
影响因子：
2.6
通讯作者：
Beall, CM
中科院分区：
文献类型：
--
作者：
Beall, CM
概要
对高海拔地区人类的研究有助于理解人类对环境的适应过程和进化。高海拔地区的独特压力是低压缺氧，这是由于随着海拔升高气压下降，与海平面相比，一次呼吸中所含的氧分子减少所致。人类在三大洲的高海拔高原聚居这一自然实验，导致了安第斯、西藏和埃塞俄比亚本土高海拔人群中两种——或许是三种——在动脉血氧含量表型上存在数量差异。本文通过展示在相同海拔下安第斯高地人与西藏人相比血红蛋白浓度更高以及血红蛋白氧饱和度百分比更高的证据，以及埃塞俄比亚高地人在这两个特征上与海平面人群无差异的证据，来说明这些对比鲜明的表型。进化过程可能对这些聚居人群产生了不同的作用，从而导致了不同的适应模式。在安第斯和西藏样本中，血红蛋白浓度具有显著的遗传性。在安第斯样本中，氧饱和度没有遗传性，但在西藏样本中却有，并且已检测到一个常染色体显性主基因与较高的氧饱和度有关。被估计极有可能具有高氧饱和度基因型的女性比被估计极有可能具有低氧饱和度基因型的女性拥有更多存活的子女。这些发现提出了一个假设，即正在进行的自然选择正在增加这个主基因位点上高饱和度等位基因的频率。
Synopsis Research on humans at high-altitudes contributes to understanding the processes of human adaptation to the environment and evolution. The unique stress at high altitude is hypobaric hypoxia caused by the fall in barometric pressure with increasing altitude and the consequently fewer oxygen molecules in a breath of air, as compared with sea level. The natural experiment of human colonization of high-altitude plateaus on three continents has resulted in two-perhaps three-quantitatively different arterial-oxygen-content phenotypes among indigenous Andean, Tibetan and Ethiopian high-altitude Populations. This paper illustrates these contrasting phenotypes by presenting evidence for higher hemoglobin concentration and percent of oxygen saturation of hemoglobin among Andean highlanders as compared with Tibetans at the same altitude and evidence that Ethiopian highlanders do not differ from sea-level in these two traits. Evolutionary processes may have acted differently on the colonizing populations to cause the different patterns of adaptation. Hemoglobin concentration has significant heritability in Andean and Tibetan samples. Oxygen saturation has no heritability in the Andean sample, but does among Tibetans where all autosomal dominant major gene for higher oxygen saturation has been detected. Women estimated with high probability to have high oxygen saturation genotypes have more surviving children than women estimated with high probability to have the low oxygen saturation genotype. These findings suggest the hypothesis that ongoing natural selection is increasing the frequency of the high saturation allele at this major gene locus.