Supergenes,紧密连锁的等位基因集,提供了一些在长期平衡选择下多态性持续存在的最壮观的例子。然而,我们仍然不了解它们的演变和坚持,尤其是面对有害元素的积累。这里,我们证明了海藻苍蝇中的一个显性超基因,Coelopafrigida,调节男性特征,可能促进异型交配和促进种内多态性。横跨两大洲,Cf-Inv(1)超基因强烈影响雄性表皮碳氢化合物(CHCs)的组成,但对雌性CHC的组成影响很小。使用气相色谱-电触感图检测,我们表明,女性可以感知男性CHC,并且基因型之间可能存在差异感知。结合我们的表型结果和RNA-seq数据,我们显示CHC生物合成的候选基因主要在男性而非女性中显示Cf-Inv(1)的差异表达。相反,用于气味检测的候选基因在两种性别中差异表达,但在超基因单倍型之间显示出高水平的差异。我们认为,超基因单倍型之间的重组减少可能导致配偶偏好的快速分歧以及男性性状之间的联系增加。和过度显性基因座。尽管在纯合子中具有有害作用,但这可能有助于维持多态性。
Supergenes, tightly linked sets of alleles, offer some of the most spectacular examples of polymorphism persisting under long-term balancing selection. However, we still do not understand their evolution and persistence, especially in the face of accumulation of deleterious elements. Here, we show that an overdominant
supergene in seaweed flies, Coelopa frigida, modulates male traits, potentially facilitating disassortative mating and promoting intraspecific polymorphism. Across two continents, the Cf-Inv(1)
supergene strongly affected the composition of male cuticular hydrocarbons (CHCs) but only weakly affected CHC composition in females. Using gas chromatography-electroantennographic detection, we show that females can sense male CHCs and that there may be differential perception between genotypes. Combining our phenotypic results with RNA-seq data, we show that candidate genes for CHC biosynthesis primarily show differential expression for Cf-Inv(1) in males but not females. Conversely, candidate genes for odorant detection were differentially expressed in both sexes but showed high levels of divergence between
supergene haplotypes. We suggest that the reduced recombination between
supergene haplotypes may have led to rapid divergence in mate preferences as well as increasing linkage between male traits, and overdominant loci. Together this probably helped to maintain the polymorphism despite deleterious effects in homozygotes.