Contrasting reproductive strategies of triploid hybrid males in vertebrate mating systems

The scarcity of parthenogenetic vertebrates is often attributed to their ‘inferior’ mode of clonal reproduction, which restricts them to self-reproduce their own genotype lineage and leaves little evolutionary potential with regard to speciation and evolution of sexual reproduction. Here, we show that for some taxa such uniformity does not hold. By using hybridogenetic water frogs (Pelophylax esculentus) as a model system, we demonstrate that triploid hybrid males from two geographic regions exhibit very different reproductive modes. With an integrative data set combining field studies, crossing experiments, flow cytometry and microsatellite analyses, we found that triploid hybrids from Central Europe are rare, occur in male sex only and form diploid gametes of a single clonal lineage. In contrast, triploid hybrids from North Western Europe are widespread, occur in both sexes and produce recombined haploid gametes. These differences translate into contrasting reproductive roles between ...孤雌生殖脊椎动物（Parthenogenetic Vertebrates）的稀缺性常被归因于其被认为‘低等’的克隆繁殖模式——该模式使其仅能自我延续自身的基因型谱系，且在物种形成与有性生殖演化领域几乎不具备进化潜力。本研究表明，对于部分分类群而言，这一普遍性结论并不成立。本研究以杂交生殖水蛙（Pelophylax esculentus）为模式实验体系，证实来自两个地理区域的三倍体杂交雄性蛙展现出截然不同的繁殖模式。本研究结合野外调查、杂交实验、流式细胞术（Flow Cytometry）与微卫星分析（Microsatellite Analyses）构建整合数据集，结果显示：中欧地区的三倍体杂交蛙仅以雄性个体存在，种群极为稀有，且仅能形成单一克隆谱系的二倍体配子。与之形成鲜明对比的是，西北欧地区的三倍体杂交蛙种群分布广泛，雌雄个体均有存在，并可产生经过重组的单倍体配子。这些差异进而导致二者在繁殖角色上呈现出截然相反的特征……