Data from: Meiotic drive influences the outcome of sexually antagonistic selection at a linked locus

Most meiotic drivers, such as the t-haplotype in Mus and the segregation distorter (SD) in Drosophila, act in a sex-specific manner, gaining a transmission advantage through one sex although suffering only the fitness costs associated with the driver in the other. Their inheritance is thus more likely through one of the two sexes, a property they share with sexually antagonistic alleles. Previous theory has shown that pairs of linked loci segregating for sexually antagonistic alleles are more likely to remain polymorphic and that linkage disequilibrium accrues between them. I probe this similarity between drive and sexual antagonism and examine the evolution of chromosomes experiencing these selection pressures simultaneously. Reminiscent of previous theory, I find that: the opportunity for polymorphism increases for a sexually antagonistic locus that is physically linked to a driving locus; the opportunity for polymorphism at a driving locus also increases when linked to a sexually antagonistic locus; and stable linkage disequilibrium accompanies any polymorphic equilibrium. Additionally, I find that drive at a linked locus favours the fixation of sexually antagonistic alleles that benefit the sex in which drive occurs. Further, I show that under certain conditions reduced recombination between these two loci is selectively favoured. These theoretical results provide clear, testable predictions about the nature of sexually antagonistic variation on driving chromosomes and have implications for the evolution of genomic architecture.

大多数减数分裂驱动因子（meiotic driver），例如小家鼠（Mus）中的t单倍型（t-haplotype）以及果蝇（Drosophila）中的分离扭曲因子（segregation distorter, SD），均以性别特异性方式发挥作用：它们通过某一性别获得传递优势，却仅在另一性别中承受与驱动因子相关的适合度成本。因此这类因子的遗传更倾向于通过两种性别之一，这一特性与性拮抗等位基因（sexually antagonistic alleles）一致。以往的理论研究表明，携带性拮抗等位基因的连锁位点对更易维持多态性，且二者之间会积累连锁不平衡（linkage disequilibrium）。本研究探讨了减数分裂驱动与性拮抗作用之间的相似性，并分析了同时承受这两类选择压力的染色体的演化过程。与以往理论结果一致，本研究发现：其一，与驱动位点物理连锁的性拮抗位点的多态性机会得以提升；其二，与性拮抗位点连锁的驱动位点的多态性机会同样增加；其三，任何多态平衡均伴随稳定的连锁不平衡。此外，本研究还发现，连锁位点上的驱动作用会偏好促进受益于驱动发生的性别的性拮抗等位基因的固定。进一步研究表明，在特定条件下，这两类位点之间的重组率降低会受到选择的青睐。这些理论结果针对驱动染色体上的性拮抗变异的本质提出了明确且可验证的预测，同时对基因组结构的演化具有重要启示意义。