Transposable element-mediated balancing selection at Hsp90 underlies embryo developmental variation
Transposable element-mediated balancing selection at Hsp90 underlies embryo developmental variation
复制标题
Hsp90 转座元件介导的平衡选择是胚胎发育变异的基础
DOI：
10.1093/molbev/msx062
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发表时间：
2017
影响因子：
10.7
通讯作者：
Le Kang
中科院分区：
文献类型：
--
作者：
Bing Chen;Bo Zhang;Lingling Xu;Qing Li;Feng Jiang;Pengcheng Yang;Yanan Xu;Le Kang
了解转座因子（te）在基因组进化和适应中的作用是一个长期追求的目标。在这里，我们提出了一种新的TE共选择模型，其中TE被一个必需基因所利用，并通过杂合子优势赋予局部适应。我们在迁徙蝗虫的基因组中发现了一个类似人类alu的TE家族，即thelm1元素，该元素含有70万份拷贝。在蝗虫自然种群中扫描lmm1插入，揭示了flm1广泛存在的高多态性。anlm1被招募到热休克蛋白90 （Hsp90）的编码区，热休克蛋白90是多种信号转导和发育途径的重要分子伴侣。只有等位基因的杂合子存在于自然种群中。在中国东部沿海地区，等位基因频率随着纬度的降低而增加，南方人群的等位基因频率甚至增加了76%。tlm1插入的侧翼区域显示选择性扫描链接的tlm1的清晰特征。m1介导的hsp90突变对蝗虫的胚胎发育有重要影响。杂合子胚胎比野生型发育更快，特别是在长时间的亲本光周期的提示下。杂合子在胚胎发育方面也表现出种群内变异的减少，即胚胎的高度发育同行性。自然发生的hsp90突变可以促进南部热带地区蝗虫的多遗传和发育同步。这些结果揭示了微进化变化背后的遗传机制，其中平衡选择可能通过必要基因的TE共选择来维持杂合子优势。
Understanding the roles of transposable elements (TEs) in the evolution of genome and adaptation is a long-sought goal. Here, we present a new model of TE co-option, in which a TE is harnessed by an essential gene and confers local adaptation through heterozygote advantage. We characterized a humanAlu-like TE family, theLm1elements, in the genome of the migratory locustLocusta migratoriathat harbors 0.7 million copies of the elements. ScanningLm1insertions in the natural locust populations revealed the widespread high polymorphism ofLm1. AnLm1was recruited into the coding region of Heat-shock protein 90 (Hsp90), an important molecular chaperone for diverse signal transduction and developmental pathways. Only heterozygotes of the allele are present in natural populations. Allele frequency increases with decreased latitudes in east coastal China, even increasing up to 76% in southern populations. Regions flanking theLm1insertion display clear signatures of a selective sweep linked toLm1. TheLm1-mediatedHsp90mutation is consequential for the embryonic development of locust. Heterozygous embryos develop faster than the wild type, particularly when cued by long-day parental photoperiod. The heterozygotes also present a reduced within-population variation in embryonic development, i.e., high developmental synchrony of embryos. The naturally occurringHsp90mutation could facilitate multivoltinism and developmental synchronization of the locust in southern tropical region. These results revealed a genetic mechanism behind microevolutionary changes in which balancing selection may have acted to maintain the heterozygote advantage through TE co-option in essential genes.