Chironomus riparius (Diptera) genome sequencing reveals the impact of minisatellite transposable elements on population divergence
Chironomus riparius (Diptera) genome sequencing reveals the impact of minisatellite transposable elements on population divergence
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DOI：
10.1111/mec.14111
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发表时间：
2017-06-01
影响因子：
4.9
通讯作者：
Pfenninger, Markus
中科院分区：
文献类型：
--
作者：
Oppold, Ann-Marie;Schmidt, Hanno;Pfenninger, Markus
活性转座因子（TE）可能会导致同种种群之间不同的基因组插入和丰度模式。在二次接触后，这种不同的遗传背景理论上可以引起经典的Dobzhansky-Muller不相容性（Dobzhansky-Muller incompatibilities，D-M），从而有助于内源性遗传障碍的进化，并最终导致群体分化。我们研究了TE丰度差异的同类种群之间的非叮咬摇蚊riparius和评估其潜在的作用，造成这些群体之间的内源性遗传不相容性。我们专注于一个摇蚊特定的TE，小卫星样的克拉元素，其活动与物种的属。利用一个新生成的和注释的基因组草图对五个天然的C. riparius人群，我们发现了高度人群特异性TE插入模式与许多私人插入。从全基因组单核苷酸多态性（SNPs）估计的成对FST和从TE估计的FST的显著相关性与漂移一致，漂移是驱动TE群体分化的主要力量。然而，由于高比例的差异固定的La-元件插入而导致的显著更高的La-元件FST水平也指示针对分离（即杂合）插入的选择。通过正反交实验和荧光原位杂交的克拉元素多线染色体，我们记录了女性生育力和染色体错配的表型效应。我们认为，对杂合的Ca-元件插入的负选择可能造成内源遗传障碍，从而在C.河岸种群因此，TE产生的内在基因组更替可能对种群分化产生直接影响，这在操作上不同于漂移和局部适应。
Active transposable elements (TEs) may result in divergent genomic insertion and abundance patterns among conspecific populations. Upon secondary contact, such divergent genetic backgrounds can theoretically give rise to classical Dobzhansky-Muller incompatibilities (DMI), thus contributing to the evolution of endogenous genetic barriers and eventually causing population divergence. We investigated differential TE abundance among conspecific populations of the nonbiting midge Chironomus riparius and evaluated their potential role in causing endogenous genetic incompatibilities between these populations. We focussed on a Chironomus-specific TE, the minisatellite-like Cla-element, whose activity is associated with speciation in the genus. Using a newly generated and annotated draft genome for a genomic study with five natural C. riparius populations, we found highly population-specific TE insertion patterns with many private insertions. A significant correlation of the pairwise FST estimated from genomewide single-nucleotide polymorphisms (SNPs) and the FST estimated from TEs is consistent with drift as the major force driving TE population differentiation. However, the significantly higher Cla-element FST level due to a high proportion of differentially fixed Cla-element insertions also indicates selection against segregating (i.e. heterozygous) insertions. With reciprocal crossing experiments and fluorescent in situ hybridization of Cla-elements to polytene chromosomes, we documented phenotypic effects on female fertility and chromosomal mispairings. We propose that the inferred negative selection on heterozygous Cla-element insertions may cause endogenous genetic barriers and therefore acts as DMI among C. riparius populations. The intrinsic genomic turnover exerted by TEs may thus have a direct impact on population divergence that is operationally different from drift and local adaptation.