Balfour Vicki L, Black Daniella, Shuker David M
School of Biology University of St Andrews St Andrews UK.
Ecol Evol. 2020 Sep 29;10(21):12224-12232. doi: 10.1002/ece3.6853. eCollection 2020 Nov.
The evolution of reproductive isolation lies at the heart of understanding the process of speciation. Of particular interest is the relationship between pre- and postzygotic reproductive isolation, and the genetic architecture of traits that contribute to one or both forms of reproductive isolation. The sibling species of seed bug and . show a classic pattern of asymmetric prezygotic reproductive isolation, with female hybridizing with male , but with no hybridization in the reciprocal direction. We have recently described a mutant pale color form of , that inherits as a single Mendelian locus and is pleiotropic for a number of other life history and behavioral traits. Here, we tested whether this locus also influences pre- and postzygotic reproductive isolation. Two sets of experimental crosses revealed that behavioral isolation varied with mutant versus wild-type phenotype for male . , with the pale form less successful at mating with female . . In terms of trying to assess postzygotic isolation, levels of hybrid offspring production were uniformly low across the experiments. However, we did obtain, for the first time, hybrid offspring from a pairing between a female and a male . In this instance, the female was of the pale mutant genotype. Together with evidence for heterozygote advantage in terms of nymph survival, we consider our results in terms of possible mechanisms of reproductive isolation between this species pair, the role of the pale mutation, and the possible genetic architectures underlying the mutation, from a single gene to a supergene.
生殖隔离的进化是理解物种形成过程的核心。特别令人感兴趣的是合子前和合子后生殖隔离之间的关系，以及导致一种或两种生殖隔离形式的性状的遗传结构。种子蝽的姐妹物种 和 表现出一种典型的不对称合子前生殖隔离模式，即 雌虫与 雄虫杂交，但反向杂交不存在。我们最近描述了 的一种突变浅色形态，它作为一个单一孟德尔位点遗传，并且对许多其他生活史和行为性状具有多效性。在这里，我们测试了这个位点是否也影响合子前和合子后生殖隔离。两组实验杂交表明， 雄虫的行为隔离随突变型与野生型表型而变化，浅色形态与 雌虫交配的成功率较低。在试图评估合子后隔离方面，整个实验中杂交后代的产生水平均较低。然而，我们首次获得了 雌虫与 雄虫配对产生的杂交后代。在这种情况下，雌虫是浅色突变基因型。结合若虫存活方面杂合子优势的证据，我们从单个基因到超基因的角度，考虑了我们关于该物种对之间生殖隔离的可能机制、浅色突变的作用以及突变潜在的可能遗传结构的结果。
