A test of genomic modularity among life-history adaptations promoting speciation with gene flow
A test of genomic modularity among life-history adaptations promoting speciation with gene flow
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生命史适应中基因组模块化的测试，通过基因流促进物种形成
DOI：
10.1111/mec.14178
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发表时间：
2017
影响因子：
4.9
通讯作者：
Feder, Jeffrey L.
中科院分区：
文献类型：
--
作者：
Ragland, Gregory J.;Doellman, Meredith M.;Meyers, Peter J.;Hood, Glen R.;Egan, Scott P.;Powell, Thomas H.;Hahn, Daniel A.;Nosil, Patrik;Feder, Jeffrey L.
具有基因流的物种形成可能需要多种性状的适应性分歧，以产生强大的基于生态的生殖隔离。因此，影响这些不同性状的错误阶段基因的广泛负多效性或物理连锁可能会阻碍物种形成，而表型性状之间的遗传独立性或“模块化”可能会减少限制并促进分化。在这里，我们通过基因分型测序（GBS）测量的 10,256 个 SNP 进行分析，测试滞育生活史的两个组成部分（初始滞育强度和滞育终止时间）的遗传学是否限制同域山楂和苹果侵染苹果蝇的宿主种族之间的分化。与滞育终止时间遗传相关的基因座主要观察到映射到基因组中 1-3 号染色体的 SNP，最显着的是显示出较高水平连锁不平衡 (LD) 的 SNP，这可能是由于倒位所致。相比之下，对初始滞育强度的选择影响了基因组所有五个主要染色体上的位点，特别是那些显示低水平 LD 的位点。遗传相关基因座缺乏重叠表明这两种滞育表型很大程度上是模块化的。然而，在 2 号染色体上，中等水平的 LD 基因座和高 LD 基因座的亚组在初始滞育强度和滞育终止时间之间表现出显着的负相关关系。因此，2 号染色体上的这些基因区域影响这两个性状，而大多数区域在很大程度上是独立的。此外，与这两种测量性状相关的基因座也往往在宿主种族之间表现出高度不同的等位基因频率。因此，不重叠遗传模块的存在可能促进了测量的生活史成分的同时、适应性分歧。
Speciation with gene flow may require adaptive divergence of multiple traits to generate strong ecologically based reproductive isolation. Extensive negative pleiotropy or physical linkage of genes in the wrong phase affecting these diverging traits may therefore hinder speciation, while genetic independence or “modularity” among phenotypic traits may reduce constraints and facilitate divergence. Here, we test whether the genetics underlying two components of diapause life history, initial diapause intensity and diapause termination timing, constrain differentiation between sympatric hawthorn and apple‐infesting host races of the flyRhagoletis pomonellathrough analysis of 10,256 SNPs measured via genotyping‐by‐sequencing (GBS). Loci genetically associated with diapause termination timing were mainly observed for SNPs mapping to chromosomes 1–3 in the genome, most notably for SNPs displaying higher levels of linkage disequilibrium (LD), likely due to inversions. In contrast, selection on initial diapause intensity affected loci on all five major chromosomes of the genome, specifically those showing low levels of LD. This lack of overlap in genetically associated loci suggests that the two diapause phenotypes are largely modular. On chromosome 2, however, intermediate level LD loci and a subgroup of high LD loci displayed significant negative relationships between initial diapause intensity and diapause termination time. These gene regions on chromosome 2 therefore affected both traits, while most regions were largely independent. Moreover, loci associated with both measured traits also tended to exhibit highly divergent allele frequencies between the host races. Thus, the presence of nonoverlapping genetic modules likely facilitates simultaneous, adaptive divergence for the measured life‐history components.