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重新审视乳糖持久性的进化:来自南亚基因组的见解
Elise Kerdoncuff1,2, Meaghan Marohn1,2, Nathan Cramer1,2
1Department of Molecular and Cell Biology, University of California, Berkeley, CA.
bioRxiv : the preprint server for biology
|November 24, 2025
概括
南亚的乳糖持续性 (LP) 与草原祖先有关,而不仅仅是自然选择. 特定的牧民群体对LP表现出强烈的选择,突出显示了复杂的进化压力.
科学领域:
- 人类进化遗传学人类进化遗传学
- 人口遗传学 人口遗传学
- 古代DNA分析 古代DNA分析
背景情况:
- 乳糖酶持久性 (LP),即成年时消化牛奶的能力,是人类的一个关键适应.
- LP与LCT基因附近的突变有关,并在欧洲人和非洲人中观察到选择过程中.
- 在依赖乳制品的南亚地区,LP的进化历史尚不清楚.
研究的目的:
- 为了研究南亚乳糖酶持久性的起源,进化史和选择性压力.
- 分析来自不同南亚人口的全基因组数据,包括古代样本.
- 了解祖先和自然选择在塑造LP流行中的相互作用.
主要方法:
- 从约8,000个现代和古老的南亚基因组 (印度,巴基斯坦,孟加拉国) 收集了全基因组数据.
- 分析了跨越~公元前3300年至公元1650年的数据,涵盖了各种各样的民族语言和生计群体.
- 采用古代DNA分析和当地祖先推断.
主要成果:
- 欧亚LP变种 (-13.910:C>T) 在南亚广泛传播,具有临床变异.
- 这种变异是在历史/中世纪时期通过草原牧民基因流入的.
- 在大多数南亚人中,LP的流行是由草原祖先解释的,但两个群体 (Toda,Gujjar) 在LCT位点表现出强烈的选择.
结论:
- 南亚LP的流行是由祖先 (草原基因流) 和局部自然选择决定的.
- 像Toda和Gujar这样的牧民团体显示出强有力的LP选择证据.
- 这项研究揭示了南亚乳糖持续性复杂的进化格局.
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