BACKGROUND Sympatric sister species provide an opportunity to investigate the genetic mechanisms and evolutionary forces that maintain species boundaries. The persistence of morphologically and genetically distinct populations in sympatry can only occur if some degree of reproductive isolation exists. A pair of sympatric sister species of Primulina (P. depressa and P. danxiaensis) was used to explore the genetic architecture of hybrid male sterility. RESULTS We mapped one major- and seven minor-effect quantitative trait loci (QTLs) that underlie pollen fertility rate (PFR). These loci jointly explained 55.4% of the phenotypic variation in the F2 population. A Bateson-Dobzhansky-Muller (BDM) model involving three loci was observed in this system. We found genotypic correlations between hybrid male sterility and flower morphology, consistent with the weak but significant phenotypic correlations between PFR and floral traits. CONCLUSIONS Hybrid male sterility in Primulina is controlled by a polygenic genetic basis with a complex pattern. The genetic incompatibility involves a three-locus BDM model. Hybrid male sterility is genetically correlated with floral morphology and divergence hitchhiking may occur between them.

中文翻译：

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同胞报春花种中杂种雄性不育的遗传基础。

背景技术同胞姐妹物种提供了研究维持物种边界的遗传机制和进化力的机会。只有在某种程度上存在生殖隔离时，才能出现形态和遗传上截然不同的种群。利用一对报春花同胞姐妹种（P. depressa和P. danxiaensis）探索杂种雄性不育的遗传结构。结果我们绘制了花粉生育率（PFR）的一个主要和七个次要数量性状位点（QTL）。这些基因座共同解释了F2群体中55.4％的表型变异。在该系统中观察到一个涉及三个基因座的Bateson-Dobzhansky-Muller（BDM）模型。我们发现杂种雄性不育与花朵形态之间的基因型相关性，与PFR和花性状之间的弱但显着的表型相关性一致。结论报春花中的杂种雄性不育是由具有复杂模式的多基因遗传基础控制的。遗传不相容性涉及三基因座BDM模型。杂种雄性不育与花的形态在遗传上相关，它们之间可能发生搭便车。