Understanding the Hidden Complexity of Latin American Population Isolates
Understanding the Hidden Complexity of Latin American Population Isolates
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DOI：
10.1016/j.ajhg.2018.09.013
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发表时间：
2018-11-01
影响因子：
9.8
通讯作者：
Lohmueller, Kirk E.
中科院分区：
文献类型：
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作者：
Mooney, Jazlyn A.;Huber, Christian D.;Lohmueller, Kirk E.
迄今为止，大多数研究的种群分离株都是从一个单一的祖先种群中发现的。因此，对混合种群分离株的人口统计学历史了解有限。在这里，我们调查的基因组多样性最近混合人口分离哥斯达黎加和哥伦比亚，并比较其多样性的基准人口分离，芬兰。这些拉丁美洲的隔离物起源于世纪，由几百名欧洲男性和美洲印第安女性的混合物，非洲创始人的贡献有限。我们检查了来自449个个体的全基因组序列数据，确定为家庭以建立多代谱系，平均测序深度约为36倍。我们发现，拉丁美洲的分离株增加了相对于芬兰的遗传多样性。然而，有一个增加的数量的身份由血统（IBD）段在拉丁美洲的分离株相对于芬兰。IBD片段的增加可能是混合群体分离株建立期间最近出现的严重群体瓶颈的结果。此外，基因组的比例，福尔斯内的一个长期运行的纯合性（ROH）在哥斯达黎加和哥伦比亚的个人是显着大于在芬兰，这表明最近的亲缘关系在拉丁美洲的分离物相对于在芬兰。最后，我们发现，最近的血缘关系增加了在纯合状态下发现的有害变体的数量，如果有害变体是隐性的，这是相关的。我们的研究表明，没有单一的基因签名的人口隔离。
Most population isolates examined to date were founded from a single ancestral population. Consequently, there is limited knowledge about the demographic history of admixed population isolates. Here we investigate genomic diversity of recently admixed population isolates from Costa Rica and Colombia and compare their diversity to a benchmark population isolate, the Finnish. These Latin American isolates originated during the 16th century from admixture between a few hundred European males and Amerindian females, with a limited contribution from African founders. We examine whole-genome sequence data from 449 individuals, ascertained as families to build mutigenerational pedigrees, with a mean sequencing depth of coverage of approximately 36x. We find that Latin American isolates have increased genetic diversity relative to the Finnish. However, there is an increase in the amount of identity by descent (IBD) segments in the Latin American isolates relative to the Finnish. The increase in IBD segments is likely a consequence of a very recent and severe population bottleneck during the founding of the admixed population isolates. Furthermore, the proportion of the genome that falls within a long run of homozygosity (ROH) in Costa Rican and Colombian individuals is significantly greater than that in the Finnish, suggesting more recent consanguinity in the Latin American isolates relative to that seen in the Finnish. Lastly, we find that recent consanguinity increased the number of deleterious variants found in the homozygous state, which is relevant if deleterious variants are recessive. Our study suggests that there is no single genetic signature of a population isolate.