在所有的动物里,人类是最会出汗的。最近哈佛大学和复旦大学的研究者合作发现,东亚人特有的一个基因变异使得东亚人更容易出汗。
研究者通过研究一个被称为EDAR370A的东亚人特有的基因变异,发现这个变异出现在3万多年前的东亚,并且改变了东亚人祖先的汗腺和毛发的密度、毛发粗细及牙齿特征。由于这个变异具备与环境适应的生存优势,它在人群中的比例迅速增加。该研究成果作为封面论文发表于2月14日出版的国际权威学术期刊《细胞》(Cell)杂志。
该课题组的汪思佳教授介绍说,这个基因变异约三万年前产生于东亚人群,最终在中国汉族人群中达到近95%。复旦大学的团队通过分析2500名汉族志愿者,发现具有这个变异的个体的汗腺密度高了约15%,毛发更粗,而且牙齿形状也有变化。哈佛大学的合作者通过动物研究证实,这个基因变异确实会影响汗腺和毛发的发育。
论文通讯作者之一、复旦大学现代人类学教育部重点实验室主任金力教授指出,东亚人的祖先3万多年前来到东亚时,最先到达东南亚。出汗能力的提高,使得我们的祖先能够更好地适应湿热环境而生存下去。所以,这个基因变异是东亚人类适应新环境的产物,而这种对环境的适应性进化正是产生当代人群间差异的重要机制之一。金力教授强调说,这次研究揭示,单个基因变异可以同时影响人类的多个形态特征。所以,为数不多的基因变异可能导致东方人与其他人种的形态差异。
这个研究的结果,对发现决定东亚人群特征的形成具有重要的意义。该团队将继续从多学科角度进一步研究,最终揭示不同人种形态差异的生物学机制。(生物谷Bioon.com)
DOI:10.1016/j.cell.2013.01.016
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Modeling Recent Human Evolution in Mice by Expression of a Selected EDAR Variant
Yana G. Kamberov, Sijia Wang, Jingze Tan, Pascale Gerbault, Abigail Wark, Longzhi Tan, Yajun Yang, Shilin Li, Kun Tang, Hua Chen, Adam Powell, Yuval Itan, Dorian Fuller, Jason Lohmueller, Junhao Mao, Asa Schachar, Madeline Paymer, Elizabeth Hostetter, Elizabeth Byrne, Melissa Burnett, Andrew P. McMahon, Mark G. Thomas, Daniel E. Lieberman, Li Jin, Clifford J. Tabin, Bruce A. Morgan, Pardis C. SabetiSee
Highlights
Selected East Asian EDAR allele, 370A, emerged in central China ~30,000 years ago
Hair, sweat, and mammary glands are altered in a 370A knockin mouse model
The novel effect of 370A on mouse sweat gland density is recapitulated in humans
Summary
An adaptive variant of the human Ectodysplasin receptor, EDARV370A, is one of the strongest candidates of recent positive selection from genome-wide scans. We have modeled EDAR370A in mice and characterized its phenotype and evolutionary origins in humans. Our computational analysis suggests the allele arose in central China approximately 30,000 years ago. Although EDAR370A has been associated with increased scalp hair thickness and changed tooth morphology in humans, its direct biological significance and potential adaptive role remain unclear. We generated a knockin mouse model and find that, as in humans, hair thickness is increased in EDAR370A mice. We identify new biological targets affected by the mutation, including mammary and eccrine glands. Building on these results, we find that EDAR370A is associated with an increased number of active eccrine glands in the Han Chinese. This interdisciplinary approach yields unique insight into the generation of adaptive variation among modern humans.