Abstract：
Research on supergenes, non-recombining genomic regions housing tightly linked genes that control complex phenotypes, has recently gained prominence in genomics. Heterostyly, a floral heteromorphism promoting outcrossing in several angiosperm families, is controlled by the S-locus supergene. The S-locus has been studied primarily in closely related Primula species and, more recently, in other groups that independently evolved heterostyly. However, it remains unknown whether genetic architecture and composition of the S-locus are maintained among species that share a common origin of heterostyly and subsequently diverged across larger time scales. To address this research gap, we present a chromosome-scale genome assembly of Primula edelbergii, a species that shares the same origin of heterostyly with Primula veris (whose S-locus has been characterized) but diverged from it 18 million years ago. Comparative genomic analyses between these two species allowed us to show, for the first time, that the S-locus can \'jump\' (i.e. translocate) between chromosomes maintaining its function in controlling heterostyly. Additionally, we found that four S-locus genes were conserved but reshuffled within the supergene, seemingly without affecting their expression, thus we could not detect changes explaining the lack of self-incompatibility in P. edelbergii. Furthermore, we confirmed that the S-locus is not undergoing genetic degeneration. Finally, we investigated P. edelbergii evolutionary history within Ericales in terms of whole genome duplications and transposable element accumulation. In summary, our work provides a valuable resource for comparative analyses aimed at investigating the genetics of heterostyly and the pivotal role of supergenes in shaping the evolution of complex phenotypes.
摘要：
关于超基因的研究，非重组基因组区域包含控制复杂表型的紧密连锁基因，最近在基因组学中获得了突出的地位。异类地，在几个被子植物家庭中促进异形的花卉异形，受S基因座超基因控制。主要在密切相关的报春花物种中研究了S基因座，最近,在其他独立进化的群体中。然而,尚不清楚S基因座的遗传结构和组成是否在具有共同起源的物种之间保持不变，并随后在更大的时间尺度上分化。为了解决这个研究空白，我们提出了报春花的染色体尺度基因组组装，与报春花（已表征其S基因座）具有相同的异型起源，但在1800万年前与之不同。这两个物种之间的比较基因组分析使我们能够证明，第一次,S基因座可以在染色体之间跳跃（即易位），保持其控制异型的功能。此外,我们发现四个S基因座基因是保守的，但在超基因中重新改组，似乎不影响他们的表达，因此，我们无法检测到的变化解释缺乏自交不亲和。此外，我们证实S基因座没有发生遗传变性。最后,我们从全基因组复制和转座因子积累的角度研究了埃里卡利卡利斯内的埃德博吉杆菌进化史。总之,我们的工作为比较分析提供了宝贵的资源，旨在研究异型遗传以及超基因在塑造复杂表型进化中的关键作用。
