Studies on polymorphisms have been foundational to our understanding of evolution. The presence of different phenotypic morphs is sometimes considered a precursor to speciation in which morphs evolve into different species. While speciation should initially reduce genetic variation in daughter versus parental species, a common pattern is the recurrence of the same phenotypic polymorphism in many species of a clade. Despite the ubiquity of these persistent polymorphisms, there is little discussion of their evolutionary origins. How does the genetic variation underpinning such polymorphisms cross speciation boundaries? What selection pressures maintain the morphs in multiple daughter species? Using diverse case studies, we highlight the characteristics of polymorphisms and selection regimes influencing the likelihood of polymorphism retention across species radiations.

多态性的研究一直是我们对进化的理解的基础。有时认为存在不同的表型形态，这是形态演变为不同物种的物种形成的前兆。虽然物种形成最初应减少子代和亲代物种的遗传变异，但常见的模式是许多进化枝物种中相同表型多态性的复发。尽管这些持久性多态性无处不在，但对其进化起源的讨论却很少。支撑这种多态性的遗传变异如何跨越物种边界？什么选择压力可以维持多个子代物种的形态？通过各种案例研究