Autosomal and X-linked single nucleotide polymorphisms reveal a steep Asian-Melanesian ancestry cline in eastern Indonesia and a sex bias in admixture rates
Autosomal and X-linked single nucleotide polymorphisms reveal a steep Asian-Melanesian ancestry cline in eastern Indonesia and a sex bias in admixture rates
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DOI：
10.1098/rspb.2009.2041
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发表时间：
2010-05-22
影响因子：
4.7
通讯作者：
Hammer, Michael F.
中科院分区：
文献类型：
--
作者：
Cox, Murray P.;Karafet, Tatiana M.;Hammer, Michael F.
亚洲大陆和新几内亚之间的地理区域的特点是许多小岛屿与孤立的人口。从表型上看，西部的群体与东南亚大陆的邻居相似，新几内亚附近的东部群体与美拉尼西亚人相似，而中间的群体在外观上是中间的。一个长期存在的问题是，这种模式是否主要反映了具有不同起源的群体之间的混合，或者自然选择是否通过对该地区人口的差异作用而形成了这种变化范围。为了解决这个问题，我们基因分型一组37个单核苷酸多态性，是进化独立的，pupestrian中性和高度信息的亚洲-美拉尼西亚血统在1430人从60个人口横跨亚洲大陆到美拉尼西亚。混合物分析显示，在印度尼西亚东部的一个狭窄的地理区域内，从亚洲到美拉尼西亚的遗传变异急剧过渡。有趣的是，这种混合渐变群大致对应于阿尔弗雷德·拉塞尔·华莱士（Alfred Russell Wallace）在1869年指出的人类表型边界。我们的结论是，这种表型梯度可能反映了两个长期分离的祖先源人口的混合，一个是从最初的美拉尼西亚人一样的居民的地区，和其他有关的亚洲群体，在旧石器时代移民和/或农业的传播。亚洲X连锁标记相对于整个过渡区的常染色体标记的频率较高，这表明混合过程是有性别偏见的，要么有利于向西扩张的父系美拉尼西亚群体或向东扩张的母系亚洲移民。在早期南岛语族社会中占主导地位的母系婚姻习俗可能是造成这种观察到的混合率性别偏见的一个因素。
The geographical region between mainland Asia and New Guinea is characterized by numerous small islands with isolated human populations. Phenotypically, groups in the west are similar to their neighbours in mainland Southeast Asia, eastern groups near New Guinea are similar to Melanesians, and intervening populations are intermediate in appearance. A long-standing question is whether this pattern primarily reflects mixing between groups with distinct origins or whether natural selection has shaped this range of variation by acting differentially on populations across the region. To address this question, we genotyped a set of 37 single nucleotide polymorphisms that are evolutionarily independent, putatively neutral and highly informative for Asian-Melanesian ancestry in 1430 individuals from 60 populations spanning mainland Asia to Melanesia. Admixture analysis reveals a sharp transition from Asian to Melanesian genetic variants over a narrow geographical region in eastern Indonesia. Interestingly, this admixture cline roughly corresponds to the human phenotypic boundary noted by Alfred Russell Wallace in 1869. We conclude that this phenotypic gradient probably reflects mixing of two long-separated ancestral source populations-one descended from the initial Melanesian-like inhabitants of the region, and the other related to Asian groups that immigrated during the Paleolithic and/or with the spread of agriculture. A higher frequency of Asian X-linked markers relative to autosomal markers throughout the transition zone suggests that the admixture process was sex-biased, either favouring a westward expansion of patrilocal Melanesian groups or an eastward expansion of matrilocal Asian immigrants. The matrilocal marriage practices that dominated early Austronesian societies may be one factor contributing to this observed sex bias in admixture rates.