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（phenotypic traits）的分化通常会促进不同谱系间的交配前生殖隔离（premating isolation），但也可能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（mechanical isolation），或是产生携带适应性不良性状（maladapted traits）的杂交后代；此外，若控制这些性状差异的等位基因（allele）会多效性地（pleiotropically）影响发育的其他环节，性状分化还可能间接导致杂交个体出现遗传不相容性（genetic incompatibilities）。
本研究测定了10种假茄属（Jaltomata，茄科Solanaceae）植物的9种交配后及内在合子后生殖障碍（postmating and intrinsic postzygotic reproductive barriers）的强度，其中包含多个花部性状高度分化的物种。为评估花部性状分化对这类交配后生殖障碍强度的相对重要性，我们采用常规检验方法与一种新型线性混合建模（linear mixed modeling）手段，分析了生殖障碍强度与花部性状分化、遗传距离、地理背景以及生态差异之间的关联。
尽管这些物种间演化关系较为密切，但所有物种对均表现出中等至极强的生殖隔离水平。然而，花部性状分化并不能稳定预测生殖障碍的强度；相较而言，遗传距离能更好地解释生殖障碍的强度差异——尽管我们在一个物种中发现了机械隔离的相关证据，且整体上跨物种对的花部性状分化与坐果隔离（fruit set isolation）间存在显著正相关关系。
总体而言，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（genome-wide genetic differentiation）的关联更为紧密，而非花部性状的分化。