Data from: Trans-oceanic genomic divergence of Atlantic cod ecotypes is associated with large inversions

Chromosomal rearrangements such as inversions can play a crucial role in maintaining polymorphism underlying complex traits and contribute to the process of speciation. In Atlantic cod (Gadus morhua), inversions of several megabases have been identified that dominate genomic differentiation between migratory and non-migratory ecotypes in the Northeast Atlantic. Here, we show that the same genomic regions display elevated divergence and contribute to ecotype divergence in the Northwest Atlantic as well. The occurrence of these inversions on both sides of the Atlantic Ocean reveals a common evolutionary origin, predating the more than 100,000 years old trans-Atlantic separation of Atlantic cod. The long-term persistence of these inversions indicates that they are maintained by selection, possibly facilitated by co-evolution of genes underlying complex traits. Our data suggest that migratory behaviour is derived from more stationary, ancestral ecotypes. Overall, we identify several large genomic regions - each containing hundreds of genes – likely involved in the maintenance of genomic divergence in Atlantic cod on both sides of the Atlantic Ocean.诸如倒位（inversion）这类染色体重排，在维持复杂性状背后的多态性方面发挥关键作用，并推动物种形成进程。在大西洋鳕（Gadus morhua）中，已有研究鉴定出数个兆碱基级别的倒位区域，这些区域主导了东北大西洋种群中洄游型与非洄游型生态型之间的基因组分化。本研究证实，西北大西洋中同样存在这类倒位区域，其所在基因组区域的分化水平显著升高，且同样参与了该区域的生态型分化过程。大西洋两岸均存在此类倒位的现象，揭示了其拥有共同的演化起源，该起源早于大西洋鳕超过10万年的跨大西洋种群分化事件。这类倒位的长期保留表明它们受到自然选择的维持，这一维持过程可能得益于复杂性状相关基因的协同演化。我们的研究数据显示，洄游行为源自更为定居的祖先生态型。综上，本研究鉴定出数个大型基因组区域——每个区域均包含数百个基因——这些区域极有可能参与维持大西洋鳕在大西洋两岸的基因组分化。