Multiple strong postmating and intrinsic postzygotic reproductive barriers isolate florally diverse species of Jaltomata (Solanaceae)

Divergence in phenotypic traits often contributes to premating isolation between lineages, but could also promote isolation at postmating stages. Phenotypic differences could directly result in mechanical isolation or hybrids with maladapted traits; alternatively, when alleles controlling these trait differences pleiotropically affect other components of development, differentiation could indirectly produce genetic incompatibilities in hybrids. Here, we determined the strength of 9 postmating and intrinsic postzygotic reproductive barriers among 10 species of Jaltomata (Solanaceae), including species with highly divergent floral traits. To evaluate the relative importance of floral trait diversification on the strength of these postmating barriers, we assessed their relationship to floral divergence, genetic distance, geographical context, and ecological differences, using conventional tests and a new linear mixed modeling approach. Despite close evolutionary relationships, all species ...

表型性状的分化通常会推动不同谱系间的交配前生殖隔离形成，同时也可在交配后阶段强化生殖隔离。表型差异可直接引发机械隔离，或是产生携带适应性不良性状的杂交后代；此外，若调控这些性状差异的等位基因会多效性影响发育的其他环节，性状分化还可间接导致杂交后代出现遗传不相容性。本研究针对10种贾尔托马塔属（Jaltomata，茄科Solanaceae）植物，其中部分类群的花部性状高度分化，测定了9种交配后内在合子后生殖隔离的强度。为评估花部性状分化对这些交配后生殖隔离强度的相对影响，本研究采用常规检验方法与新型线性混合模型，分析了生殖隔离强度与花部分化、遗传距离、地理背景及生态差异之间的关联。尽管这些类群间亲缘关系密切，但所有物种……