Population genomics of the inbred Scandinavian wolf.
Population genomics of the inbred Scandinavian wolf.
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DOI：
10.1111/j.1365-294x.2009.04120.x
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发表时间：
2009-04
影响因子：
4.9
通讯作者：
Ellegren H
中科院分区：
文献类型：
--
作者：
Hagenblad J;Olsson M;Parker HG;Ostrander EA;Ellegren H
斯堪的纳维亚狼种群代表了一个遗传上最好的例子，一个严重的自然种群（只有两个创始人），以及如何增加新的遗传物质（一个移民）可以至少暂时提供“遗传拯救”。然而，近亲繁殖衰退已被观察到在这个人口和在没有额外的移民，其长期生存能力受到质疑。为了研究近亲繁殖和选择对基因组多样性的影响，我们用分布在所有常染色体和X染色体上的大约250个微卫星标记进行了基因组扫描。我们发现连锁不平衡（LD），延伸到50 Mb的距离，超过了迄今为止研究的大多数远系繁殖物种。LD在X染色体上特别明显。观察到的基因组杂合性的总体水平与基于已知种群历史的模拟没有显着偏离，这不支持杂合子的普遍选择。然而，我们发现的证据支持平衡选择在一些位点，也有证据表明在其他位点的定向选择。对于23号染色体上的标记，选择信号特别强，表明即使在这个非常小的群体中也可能发生了针对有害等位基因的纯化选择。这些数据表明，人口基因组学允许探索的影响，中性和非中性的进化在一个更精细的规模比以前可能的。
The Scandinavian wolf population represents one of the genetically most well characterized examples of a severely bottlenecked natural population (with only two founders), and of how the addition of new genetic material (one immigrant) can at least temporarily provide a “genetic rescue”. However, inbreeding depression has been observed in this population and in the absence of additional immigrants, its long-term viability is questioned. To study the effects of inbreeding and selection on genomic diversity, we performed a genomic scan with approximately 250 microsatellite markers distributed across all autosomes and the X chromosome. We found linkage disequilibrium (LD) that extended up to distances of 50 Mb, exceeding that of most outbreeding species studied thus far. LD was particularly pronounced on the X chromosome. Overall levels of observed genomic heterozygosity did not deviate significantly from simulations based on known population history, giving no support for a general selection for heterozygotes. However, we found evidence supporting balancing selection at a number of loci and also evidence suggesting directional selection at other loci. For markers on chromosome 23, the signal of selection was particularly strong indicating that purifying selection against deleterious alleles may have occurred even in this very small population. These data suggest that population genomics allows the exploration of the effects of neutral and non-neutral evolution on a finer scale than what has previously been possible.