Global allele polymorphism indicates a high rate of allele genesis at a locus under balancing selection
Global allele polymorphism indicates a high rate of allele genesis at a locus under balancing selection
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全局等位基因多态性表明平衡选择下某个位点的等位基因发生率很高
DOI：
10.1038/s41437-020-00358-w
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发表时间：
2020-08-27
期刊：
影响因子：
3.8
通讯作者：
Gloag, Rosalyn
中科院分区：
文献类型：
--
作者：
Ding, Guiling;Hasselmann, Martin;Gloag, Rosalyn
当选择倾向于稀有等位基因而不是常见等位基因时（以负频率依赖选择的形式平衡选择），一个基因座可能保持大量等位基因，每个等位基因的频率相似。为了更好地了解等位基因丰富度是如何产生和维持在这样的位点，我们评估了201个亚洲蜜蜂（Apis cerana）的互补性别决定因子（csd）序列，从其范围内取样。蜜蜂是单倍二倍体;半合子发育为雄性，杂合子发育为雌性，而纯合子是致命的。因此，csdis处于强烈的负频率依赖性选择下，因为稀有等位基因不太可能以致命的纯合形式结束。我们在A中找到了这个。与其他蜜蜂一样，在中华蜜蜂中，高变区的等位基因之间的几个氨基酸差异就足以触发雌性发育。然后，我们表明，虽然等位基因谱系分布在不同的地理区域，等位基因分化是高的人群之间，与mostcsdalleles（86.3%）检测到只有一个样本位置。此外，高变区的核苷酸多样性表明最近出现的等位基因过多，可能与亚洲自末次冰期以来的人口扩张有关。只有南太平洋的新入侵种群才拥有大部分csd等位基因。总之，A.研究表明，高突变率和平衡选择共同作用，在蜜蜂性位点产生高速率的等位基因发生和更替，这反过来又导致其异常高的局部和全局多态性。
When selection favours rare alleles over common ones (balancing selection in the form of negative frequency-dependent selection), a locus may maintain a large number of alleles, each at similar frequency. To better understand how allelic richness is generated and maintained at such loci, we assessed 201 sequences of thecomplementary sex determiner(csd) of the Asian honeybee (Apis cerana), sampled from across its range. Honeybees are haplodiploid; hemizygotes atcsddevelop as males and heterozygotes as females, while homozygosity is lethal. Thus,csdis under strong negative frequency-dependent selection because rare alleles are less likely to end up in the lethal homozygous form. We find that inA. cerana, as in otherApis, just a few amino acid differences betweencsdalleles in the hypervariable region are sufficient to trigger female development. We then show that while allelic lineages are spread across geographical regions, allelic differentiation is high between populations, with mostcsdalleles (86.3%) detected in only one sample location. Furthermore, nucleotide diversity in the hypervariable region indicates an excess of recently arisen alleles, possibly associated with population expansion across Asia since the last glacial maximum. Only the newly invasive populations of the Austral-Pacific share most of theircsdalleles. In all, the geographic patterns ofcsddiversity inA. ceranaindicate that high mutation rates and balancing selection act together to produce high rates of allele genesis and turnover at the honeybee sex locus, which in turn leads to its exceptionally high local and global polymorphism.