Ontogenetic stage-specific quantitative trait loci contribute to divergence in developmental trajectories of sexually dimorphic fins between medaka populations

Sexual dimorphism can evolve when males and females differ in phenotypic optima. Genetic constraints can, however, limit the evolution of sexual dimorphism. One possible constraint is derived from alleles expressed in both sexes. Because males and females share most of their genome, shared alleles with different fitness effects between sexes are faced with intralocus sexual conflict. Another potential constraint is derived from genetic correlations between developmental stages. Sexually dimorphic traits are often favoured at adult stages, but selected against as juvenile, so developmental decoupling of traits between ontogenetic stages may be necessary for the evolution of sexual dimorphism in adults. Resolving intralocus conflicts between sexes and ages is therefore a key to the evolution of age-specific expression of sexual dimorphism. We investigated the genetic architecture of divergence in the ontogeny of sexual dimorphism between two populations of the Japanese medaka (Oryzias lat...

当雄性与雌性的表型最优值存在差异时，性二态性（Sexual dimorphism）便可能发生演化。然而，遗传限制（Genetic constraints）会制约性二态性的演化进程。其中一种潜在限制源于在两性中均有表达的等位基因（alleles）：由于雌雄共享大部分基因组，那些在两性间具有不同适合度效应的共享等位基因将面临基因座内性冲突（intralocus sexual conflict）。另一种潜在限制则来自发育阶段间的遗传相关性（genetic correlations）：性二态性状（Sexually dimorphic traits）通常在成体阶段受选择青睐，却在幼体阶段遭选择抑制，因此，若要促成成体性二态性的演化，需在个体发育阶段间实现性状的发育解耦（developmental decoupling）。由此可见，解决性别与年龄间的基因座内冲突，是年龄特异性性二态性表达演化的关键。我们探究了日本青鳉（Japanese medaka，Oryzias lat...）两个种群间性二态性个体发育分化的遗传结构（genetic architecture）。