Ecological speciation occurs when reproductive isolation evolves as a byproduct of adaptive divergence between populations. Selection favouring gene regulatory divergence between species could result in transgressive levels of gene expression in F1 hybrids that may lower hybrid fitness. We combined 58 resequenced genomes with 124 transcriptomes to identify patterns of hybrid gene misexpression that may be driven by adaptive regulatory divergence within a young radiation of Cyprinodon pupfishes, which consists of a dietary generalist and two trophic specialists—a molluscivore and a scale‐eater. We found more differential gene expression between closely related sympatric specialists than between allopatric generalist populations separated by 1,000 km. Intriguingly, 9.6% of genes that were differentially expressed between sympatric species were also misexpressed in F1 hybrids. A subset of these genes were in highly differentiated genomic regions and enriched for functions important for trophic specialization, including head, muscle and brain development. These regions also included genes that showed evidence of hard selective sweeps and were significantly associated with oral jaw length—the most rapidly diversifying skeletal trait in this radiation. Our results indicate that divergent ecological selection in sympatry can contribute to hybrid gene misexpression which may act as a reproductive barrier between nascent species.

中文翻译：

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同源性的生态分歧导致杂种中的基因错误表达。


当生殖隔离作为种群之间适应性分化的副产品而进化时，生态物种形成就会发生。有利于物种间基因调控差异的选择可能会导致 F1 杂种中基因表达水平超出标准，从而降低杂种适应性。我们将 58 个重新测序的基因组与 124 个转录组结合起来，以确定杂种基因错误表达的模式，这种模式可能是由鲤鱼幼鱼体内的适应性调节分歧驱动的，该鱼由一个饮食通才和两个营养专家（一个软体动物和一个食鳞动物）组成。我们发现，密切相关的同域专家之间的基因表达差异比相距 1,000 公里的异域通才群体之间的基因表达差异更大。有趣的是，同域物种之间差异表达的基因中有 9.6% 在 F1 杂种中也被错误表达。这些基因的一个子集位于高度分化的基因组区域，并且富含对营养专门化重要的功能，包括头部、肌肉和大脑发育。这些区域还包括显示出硬选择性扫描证据的基因，并且与口颌长度显着相关——这是该辐射中变化最快的骨骼特征。我们的结果表明，同源生态选择的不同可能导致杂种基因的错误表达，这可能成为新生物种之间的繁殖障碍。