Gramlich Susanne, Liu Xiaodong, Favre Adrien, Buerkle C Alex, Karrenberg Sophie
Department of Ecology and Genetics, Plant Ecology and Evolution, Uppsala University, Norbyvägen 18D, 75267, Uppsala, Sweden.
Department of Biology, The Bioinformatics Center, University of Copenhagen, Ole Maaløes Vej 5, 2200, Copenhagen, Denmark.
New Phytol. 2022 Aug;235(4):1641-1652. doi: 10.1111/nph.18260. Epub 2022 Jun 23.
Ecological differentiation can drive speciation but it is unclear how the genetic architecture of habitat-dependent fitness contributes to lineage divergence. We investigated the genetic architecture of cumulative flowering, a fitness component, in second-generation hybrids between Silene dioica and Silene latifolia transplanted into the natural habitat of each species. We used reduced-representation sequencing and Bayesian sparse linear mixed models (BSLMMs) to analyze the genetic control of cumulative flowering in each habitat. Our results point to a polygenic architecture of cumulative flowering. Allelic effects were mostly beneficial or deleterious in one habitat and neutral in the other. Positive-effect alleles often were derived from the native species, whereas negative-effect alleles, at other loci, tended to originate from the non-native species. We conclude that ecological differentiation is governed and maintained by many loci with small, habitat-dependent effects consistent with conditional neutrality. This pattern may result from differences in selection targets in the two habitats and from environmentally dependent deleterious load. Our results further suggest that selection for native alleles and against non-native alleles acts as a barrier to gene flow between species.
生态分化可推动物种形成，但尚不清楚依赖栖息地的适合度的遗传结构如何促进谱系分化。我们研究了在移植到每个物种自然栖息地的 dioica蝇子草和宽叶蝇子草的第二代杂交种中，作为适合度组成部分的累积开花的遗传结构。我们使用简化基因组测序和贝叶斯稀疏线性混合模型（BSLMMs）来分析每个栖息地中累积开花的遗传控制。我们的结果表明累积开花具有多基因结构。等位基因效应在一个栖息地大多是有益的或有害的，而在另一个栖息地是中性的。具有正向效应的等位基因通常来自本地物种，而在其他位点具有负向效应的等位基因则倾向于源自非本地物种。我们得出结论，生态分化由许多具有小的、依赖栖息地的效应且符合条件中性的位点所控制和维持。这种模式可能源于两个栖息地中选择目标的差异以及环境依赖的有害负荷。我们的结果进一步表明，对本地等位基因的选择和对非本地等位基因的排斥充当了物种间基因流动的障碍。
