Data from: 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 pairs showed moderate to strong isolation. Nonetheless, floral trait divergence was not a consistent predictor of the strength of isolation; instead this was best explained by genetic distance, although we found evidence for mechanical isolation in one species, and an overall positive relationship between floral trait divergence and fruit set isolation across species pairs. Overall, our data indicate that intrinsic postzygotic isolation is more strongly associated with genome-wide genetic differentiation, rather than floral divergence.

表型性状分化通常会推动类群间的交配前生殖隔离形成，同时也可能在交配后阶段强化生殖隔离作用。表型差异可直接引发机械隔离，或是产生性状适配不良的杂交后代；此外，若调控这些性状差异的等位基因存在多效性，进而影响发育的其他环节，则性状分化还可间接导致杂交个体出现遗传不相容性。本研究针对10个Jaltomata属（茄科）物种（涵盖花部性状高度分化的类群），测定了9类交配后及内在合子后生殖隔离的强度。为评估花部性状分化对这类交配后生殖隔离强度的相对贡献，本研究采用常规检验方法与全新的线性混合模型，分析了生殖隔离强度与花部性状分化、遗传距离、地理背景及生态差异之间的关联。尽管这些类群演化关系紧密，但所有物种种对均表现出中等至较强的生殖隔离。不过，花部性状分化并非生殖隔离强度的稳定预测指标；遗传距离反而能更好地解释隔离强度的差异，尽管本研究在单个物种中发现了机械隔离的相关证据，且整体而言，物种种对间的花部性状分化与坐果隔离强度呈正相关关系。综合来看，本研究数据表明，内在合子后生殖隔离与全基因组遗传分化的关联更为密切，而非花部性状分化。