Department of Zoology, University of Otago, Dunedin, 9016, New Zealand.
Department of Biological Sciences, Simon Fraser University, Burnaby, V5A 1S6, Canada.
Evolution. 2022 Jun;76(6):1170-1182. doi: 10.1111/evo.14494. Epub 2022 May 1.
Speciation is less likely to occur when there is gene flow between nascent species. Natural selection can oppose gene flow and promote speciation if there is variation in ecological conditions among the nascent species' locations. Previous theory on ecological speciation with gene flow has focused primarily on the role of genetic variation in ecological traits, largely neglecting the role of nongenetic inheritance or transgenerational plasticity. Here, we build and analyze models incorporating both genetic and epigenetic inheritance, the latter representing a form of nongenetic inheritance. We investigate the rate of speciation for a population that inhabits two patches connected by migration, and find that adaptively biased epigenetic induction can speed up or slow down speciation, depending on the form of the map from genotype and epigenotype to phenotype. While adaptively relevant epigenetic variation can speed up speciation by reducing the fitness of migrants and hybrids, it can also slow down speciation. This latter effect occurs when the epialleles are able to achieve adaptation faster than the genetic alleles, thereby weakening selection on the latter.
当新生物种之间存在基因流时，物种形成的可能性就会降低。如果新生物种的栖息地在生态条件上存在差异，自然选择可以对抗基因流并促进物种形成。先前关于有基因流的生态物种形成的理论主要集中在生态特征的遗传变异上，在很大程度上忽略了非遗传继承或跨代可塑性的作用。在这里，我们构建并分析了包含遗传和表观遗传继承的模型，后者代表了一种非遗传继承形式。我们研究了一个居住在两个由迁移连接的斑块中的种群的物种形成速度，发现适应性偏向的表观遗传诱导可以加快或减缓物种形成，具体取决于从基因型和表型到表型的映射形式。虽然适应性相关的表观遗传变异可以通过降低移民和杂种的适应性来加快物种形成，但它也可以减缓物种形成。当表观等位基因比遗传等位基因更快地适应时，就会出现这种相反的效果，从而削弱了对后者的选择。
