Evolution of putative barrier loci at an intermediate stage of speciation with gene flow in campions (Silene)

Understanding the origin of new species is a central goal in evolutionary biology. Diverging lineages often evolve highly heterogeneous patterns of genetic differentiation; however, the underlying mechanisms are not well understood. We investigated evolutionary processes governing genetic differentiation between the hybridizing campions Silene dioica (L.) Clairv. and S. latifolia Poiret. Demographic modeling indicated that the two species diverged with gene flow. The best-supported scenario with heterogeneity in both migration rate and effective population size suggested that a small proportion of the loci evolved without gene flow. Differentiation (FST) and sequence divergence (dXY) were correlated and both tended to peak in the middle of most linkage groups, consistent with reduced gene flow at highly differentiated loci. Highly differentiated loci further exhibited signatures of selection. In between-species population pairs, isolation by distance was stronger for genomic regions wit...

理解新物种的起源是进化生物学的核心目标。分化的谱系往往会形成高度异质的遗传分化模式；然而，其潜在机制尚未得到充分理解。我们研究了调控杂交剪秋罗属植物Silene dioica (L.) Clairv.与S. latifolia Poiret之间遗传分化的进化过程。种群统计建模表明，这两个物种在存在基因流的情况下分化。迁移率和有效种群大小均存在异质性的最优支持场景显示，小部分基因座在无基因流的情况下进化。分化程度（FST）与序列分歧（dXY）呈相关关系，且两者在大多数连锁群的中部趋于达到峰值，这与高度分化基因座处基因流减少的情况一致。高度分化的基因座进一步表现出选择信号。在种间种群对中，距离隔离在基因组区域...