EVIDENCE OF ADAPTATION FROM ANCESTRAL VARIATION IN YOUNG POPULATIONS OF BEACH MICE
EVIDENCE OF ADAPTATION FROM ANCESTRAL VARIATION IN YOUNG POPULATIONS OF BEACH MICE
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DOI：
10.1111/j.1558-5646.2012.01669.x
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发表时间：
2012-10-01
期刊：
影响因子：
3.3
通讯作者：
Hoekstra, Hopi E.
中科院分区：
文献类型：
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作者：
Domingues, Vera S.;Poh, Yu-Ping;Hoekstra, Hopi E.
为了了解生物如何适应新的栖息地，这涉及人口和选择事件，我们需要了解种群的进化历史和选择的等位基因。在自然界中，仍然很少有精确的突变（因此，定义的等位基因）有助于适应性变化;一个例外是在佛罗里达墨西哥湾沿岸的桑迪定居的老田鼠（Peromyscus polionotus）的色素沉着的遗传基础。为了量化基因组的殖民化的影响，以及选择的签名，我们重新测序5000 1.5 kb的非编码位点，以及周围的黑皮质素-1受体（Mc 1 r），一个基因，有助于色素沉着的差异，在海滩和大陆人口的160 kb的基因组区域。使用全基因组系统发育的方法，我们恢复了一个单一的单系组组成的海滩小鼠，符合一个单一的殖民化事件的墨西哥湾沿岸。我们还发现了一个严重的创始人事件的证据，估计发生在不到3000年前。在这种人口背景下，我们发现，所有的海滩亚种共享一个单一的衍生轻Mc 1 r等位基因，这可能是从起源于大陆的常设遗传变异选择。令人惊讶的是，我们无法确定一个明确的选择在Mc 1 r区域的签名，尽管独立的证据表明，这个位点有助于适应性着色。尽管如此，这些数据使我们能够重建和比较种群和等位基因的进化历史，以更好地了解适应性进化是如何在新栖息地殖民化后在自然界中进行的。
To understand how organisms adapt to novel habitats, which involves both demographic and selective events, we require knowledge of the evolutionary history of populations and also selected alleles. There are still few cases in which the precise mutations (and hence, defined alleles) that contribute to adaptive change have been identified in nature; one exception is the genetic basis of camouflaging pigmentation of oldfield mice (Peromyscus polionotus) that have colonized the sandy dunes of Florida's Gulf Coast. To quantify the genomic impact of colonization as well as the signature of selection, we resequenced 5000 1.5-kb noncoding loci as well as a 160-kb genomic region surrounding the melanocortin-1 receptor (Mc1r), a gene that contributes to pigmentation differences, in beach and mainland populations. Using a genome-wide phylogenetic approach, we recovered a single monophyletic group comprised of beach mice, consistent with a single colonization event of the Gulf Coast. We also found evidence of a severe founder event, estimated to have occurred less than 3000 years ago. In this demographic context, we show that all beach subspecies share a single derived light Mc1r allele, which was likely selected from standing genetic variation that originated in the mainland. Surprisingly, we were unable to identify a clear signature of selection in the Mc1r region, despite independent evidence that this locus contributes to adaptive coloration. Nonetheless, these data allow us to reconstruct and compare the evolutionary history of populations and alleles to better understand how adaptive evolution, following the colonization of a novel habitat, proceeds in nature.