The Genomic Architecture of a Rapid Island Radiation: Recombination Rate Variation, Chromosome Structure, and Genome Assembly of the Hawaiian Cricket Laupala
The Genomic Architecture of a Rapid Island Radiation: Recombination Rate Variation, Chromosome Structure, and Genome Assembly of the Hawaiian Cricket Laupala
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DOI：
10.1534/genetics.118.300894
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发表时间：
2018-08-01
期刊：
影响因子：
3.3
通讯作者：
Shaw, Kerry L.
中科院分区：
文献类型：
--
作者：
Blankers, Thomas;Oh, Kevin P.;Shaw, Kerry L.
表型进化和物种形成在许多方面依赖于重组。在种群内，重组可以通过将有利的突变聚集在一起并使有益和有害的等位基因分离来促进适应。当种群分化时，交换会产生不适应的重组体，阻碍或逆转多样化。由于基因组重排，修饰等位基因，和内在的染色体特性抑制重组可能会提供一个盾牌，对适应不良的基因流侵蚀coadapted基因复合体。理论和实证结果都支持这种关系。然而，在行为隔离的背景下，这种关系知之甚少，其中共同进化的信号和偏好是主要的杂交障碍。在这里，我们研究的基因组结构最近分歧，性隔离夏威夷剑尾蟋蟀（劳帕拉）。我们组装一个从头基因组，并产生三个密集的连锁图谱从种间杂交。与基于该物种最近的分歧和实验室中成功杂交的预期一致，连锁图高度共线，没有显示大规模染色体重排的证据。接下来，这些图谱被用于将组装锚到假分子上，并估计整个基因组的重组率，以检验参与行为隔离（歌曲和偏好分歧）的基因座位于低种间重组区域的假设。与我们的预期相反，男性歌曲和女性偏好QTL共定位的基因组区域与特别低的重组率无关。这项研究提供了一个新兴的进化遗传学模型系统的重要的新的基因组资源，并表明，性状偏好的协同进化不一定是促进局部抑制重组。
Phenotypic evolution and speciation depend on recombination in many ways. Within populations, recombination can promote adaptation by bringing together favorable mutations and decoupling beneficial and deleterious alleles. As populations diverge, crossing over can give rise to maladapted recombinants and impede or reverse diversification. Suppressed recombination due to genomic rearrangements, modifier alleles, and intrinsic chromosomal properties may offer a shield against maladaptive gene flow eroding coadapted gene complexes. Both theoretical and empirical results support this relationship. However, little is known about this relationship in the context of behavioral isolation, where coevolving signals and preferences are the major hybridization barrier. Here we examine the genomic architecture of recently diverged, sexually isolated Hawaiian swordtail crickets (Laupala). We assemble a de novo genome and generate three dense linkage maps from interspecies crosses. In line with expectations based on the species' recent divergence and successful interbreeding in the laboratory, the linkage maps are highly collinear and show no evidence for large-scale chromosomal rearrangements. Next, the maps were used to anchor the assembly to pseudomolecules and estimate recombination rates across the genome to test the hypothesis that loci involved in behavioral isolation (song and preference divergence) are in regions of low interspecific recombination. Contrary to our expectations, the genomic region where a male song and female preference QTL colocalize is not associated with particularly low recombination rates. This study provides important novel genomic resources for an emerging evolutionary genetics model system and suggests that trait-preference coevolution is not necessarily facilitated by locally suppressed recombination.