Data from: Relative strength of fine-scale spatial genetic structure in paternally vs biparentally inherited DNA in a dioecious plant depends on both sex proportions and pollen-to-seed dispersal ratio

In plants, the spatial genetic structure (SGS) is shaped mainly by gene dispersal and effective population density. Among additional factors, the mode of DNA inheritance and dioecy influence SGS. However, their joint impact on SGS remains unclear, especially in the case of paternally inherited DNA. Using theoretical approximations and computer simulations, here we showed that the relative intensity of SGS measured in paternally and biparentally inherited DNA in a dioecious plant population depends on both the proportion of males and the pollen-to-seed dispersal ratio. As long as males do not prevail in a population, SGS is more intense in paternally than biparentally inherited DNA. When males prevail, the intensity of SGS in paternally vs biparentally inherited DNA depends on the compound effect of sex proportions and the pollen-to-seed dispersal ratio. To empirically validate our predictions, we used the case of Taxus baccata, a dioecious European tree. First, we showed that mitochondrial DNA (mtDNA) in T. baccata is predominantly (98%) paternally inherited. Subsequently, using nuclear DNA (nuDNA) and mitochondrial microsatellite data, we compared the fine-scale SGS intensity at both marker types in two natural populations. The population with equal sex proportions showed stronger SGS in mtDNA than in nuDNA. On the other hand, we found lower SGS intensity in mtDNA than in nuDNA in the population with 67% males. Thus, the empirical results provided good support for the theoretical predictions, suggesting that knowledge about SGS in paternally vs biparentally inherited DNA may provide insight into effective sex proportions within dioecious populations.

在植物中，空间遗传结构（spatial genetic structure, SGS）主要由基因扩散与有效种群密度塑造。除上述核心影响因素外，DNA遗传模式与雌雄异株特性同样会对SGS产生作用。然而，二者对SGS的联合影响仍未明确，尤其是针对父系遗传DNA的相关研究。本研究通过理论近似与计算机模拟证实：在雌雄异株植物种群中，基于父系与双亲遗传DNA测得的SGS相对强度，同时取决于种群雄性比例与花粉-种子扩散比。只要种群中雄性不占优势，父系遗传DNA的SGS强度便高于双亲遗传DNA；当雄性占据多数时，二者的SGS强度对比则由性比例与花粉-种子扩散比的复合效应共同决定。为实证验证上述理论预测，我们以欧洲雌雄异株树种欧洲红豆杉（Taxus baccata）为研究对象。首先证实，欧洲红豆杉的线粒体DNA（mitochondrial DNA, mtDNA）以98%的比例呈现父系遗传特征。随后，利用核DNA（nuclear DNA, nuDNA）与线粒体微卫星数据，我们对两个自然种群中两类标记的精细尺度SGS强度进行了对比分析。在性比例均等的种群中，mtDNA的SGS强度高于nuDNA；而在雄性占比67%的种群中，mtDNA的SGS强度则低于nuDNA。综上，实证结果为理论预测提供了有力支撑，这表明针对父系与双亲遗传DNA的SGS研究，可帮助我们洞悉雌雄异株种群内的有效性比例情况。