Support from the relationship of genetic and geographic distance in human populations for a serial founder effect originating in Africa
Support from the relationship of genetic and geographic distance in human populations for a serial founder effect originating in Africa
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DOI：
10.1073/pnas.0507611102
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发表时间：
2005-11-01
影响因子：
11.1
通讯作者：
Cavalli-Sforza, LL
中科院分区：
文献类型：
--
作者：
Ramachandran, S;Deshpande, O;Cavalli-Sforza, LL
距离隔离的平衡模型预测遗传分化随着地理距离的增加而增加。在这里，我们发现一个线性关系的遗传和地理距离在世界范围内的人口样本，与拟合线的混合或极端隔离解释的主要偏差。地理距离和遗传分化（F-ST）的相关性之间存在着密切的关系和地理格局的杂合性跨种群。考虑到世界范围内的一组地理位置作为人类扩张的可能来源，我们发现，在全球分布的人口的数据集的杂合性是最好的解释起源于非洲的扩张，没有地理起源以外的非洲帐户，以及观察到的遗传多样性模式。虽然F-ST和地理距离之间的关系已被解释为在过去的漂移和扩散的平衡模型的结果，模拟表明，在这个数据集的杂合性的地理模式是一致的，从一个单一的起源一系列创始人效应的模型。鉴于这种连续创始人的情况下，遗传和地理距离之间的关系使我们能够推导出漂移和自然选择对人类遗传变异的影响的界限。
Equilibrium models of isolation by distance predict an increase in genetic differentiation with geographic distance. Here we find a linear relationship between genetic and geographic distance in a worldwide sample of human populations, with major deviations from the fitted line explicable by admixture or extreme isolation. A close relationship is shown to exist between the correlation of geographic distance and genetic differentiation (as measured by F-ST) and the geographic pattern of heterozygosity across populations. Considering a worldwide set of geographic locations as possible sources of the human expansion, we find that heterozygosities in the globally distributed populations of the data set are best explained by an expansion originating in Africa and that no geographic origin outside of Africa accounts as well for the observed patterns of genetic diversity. Although the relationship between F-ST and geographic distance has been interpreted in the past as the result of an equilibrium model of drift and dispersal, simulation shows that the geographic pattern of heterozygosities in this data set is consistent with a model of a serial founder effect starting at a single origin. Given this serial-founder scenario, the relationship between genetic and geographic distance allows us to derive bounds for the effects of drift and natural selection on human genetic variation.