Out of Africa and back again: Nested cladistic analysis of human Y chromosome variation
Out of Africa and back again: Nested cladistic analysis of human Y chromosome variation
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DOI：
10.1093/oxfordjournals.molbev.a025939
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发表时间：
1998-04-01
影响因子：
10.7
通讯作者：
Zegura, SL
中科院分区：
文献类型：
--
作者：
Hammer, MF;Karafet, T;Zegura, SL
我们调查了来自非洲、亚洲、欧洲、大洋洲和新大陆的1544个个体的Y染色体上的9个双等位多态性位点。对这9个位点的系统发育分析结果显示，这棵树有10个不同的Y单倍型，合并时间约为15万年。这10个单倍型在人群中分布不均匀：5个局限于特定的大陆，2个在非洲和欧洲共有，1个只存在于旧大陆，2个在所有被调查的地理区域都有发现。祖先的单倍型仅限于非洲人群。随机排列程序揭示了这一父本遗传变异的地理结构的统计显著模式。嵌套枝系分析的结果表明，这些地理关联是通过一系列过程产生的，包括有限的、反复的基因流动（距离隔离）和范围扩大。我们推断，在嵌套分支分析中，最古老的事件之一是非洲以外的范围扩张，导致整个旧大陆的Y染色体完全替换，这一发现与许多版本的非洲外替换模型一致。第二次也是更近的一次范围扩张将亚洲Y染色体带回了非洲，但没有取代非洲本土男性的基因库。因此，以前在非洲观察到的高水平的Y染色体遗传多样性可能部分归因于双向人口流动。最后，将我们的结果与人类mtDNA和β -珠蛋白的嵌套分支分析结果进行比较，揭示了男性和女性在群体历史（范围扩展）和群体结构（循环基因流动）的相对作用方面的不同推断模式，从而为人类进化模型增加了一个新的性别特异性成分。
We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544 individuals from Africa, Asia, Europe, Oceania, and the New World. Phylogenetic analyses of these nine sites resulted in a tree for 10 distinct Y haplotypes with a coalescence time of similar to 150,000 years. The 10 haplotypes were unevenly distributed among human populations: 5 were restricted to a particular continent, 2 were shared between Africa and Europe, 1 was present only in the Old World, and 2 were found in all geographic regions surveyed. The ancestral haplotype was limited to African populations. Random permutation procedures revealed statistically significant patterns of geographical structuring of this paternal genetic variation. The results of a nested cladistic analysis indicated that these geographical associations arose through a combination of processes, including restricted, recurrent gene flow (isolation by distance) and range expansions. We inferred that one of the oldest events in the nested cladistic analysis was a range expansion out of Africa which resulted in the complete replacement of Y chromosomes throughout the Old World, a finding consistent with many versions of the Out of Africa Replacement Model. A second and more recent range expansion brought Asian Y chromosomes back to Africa without replacing the indigenous African male gene pool. Thus, the previously observed high levels of Y chromosomal genetic diversity in Africa may be due in part to bidirectional population movements. Finally, a comparison of our results with those from nested cladistic analyses of human mtDNA and beta-globin data revealed different patterns of inferences for males and females concerning the relative roles of population history (range expansions) and population structure (recurrent gene flow), thereby adding a new sex-specific component to models of human evolution.