When a clonal genome finds its way back to a sexual species: evidence from ongoing but rare introgression in the hybridogenetic water frog complex

Besides several exceptions, asexual metazoans are usually viewed as ephemeral sinks for genomes, which become ‘frozen’ in clonal lineages after their emergence from ancestral sexual species. Here, we investigated whether and at what rate the asexuals are able to introgress their genomes back into the parental sexual population, thus more or less importantly affecting the gene pools of sexual species. We focused on hybridogenetic hybrids of western Palaearctic water frogs (Pelophylax esculentus), which originate through hybridization between P. ridibundus and P. lessonae, but transmit only clonal ridibundus genome into their gametes. Although usually mating with P. lessonae, P. esculentus may upon mating with P. ridibundus or another hybrid produce sexually reproducing P. ridibundus offspring with the introgressed ex-clonal genome. We compared the rate of nuclear amplified fragment length polymorphism (AFLP) and mitochondrial introgression in two types of populations, that is, those wher...除少数例外外，无性生殖多细胞动物（asexual metazoans）通常被视作基因组的暂时性储库，其基因组自祖先有性物种起源后，便以克隆谱系（clonal lineages）的形式被“冻结”。本研究旨在探究这类无性生殖类群能否将其基因组渐渗回亲本有性种群，以及该渐渗过程的发生速率，进而明确其对有性物种种群基因库的影响程度。我们以古北界西部的食用侧褶蛙（Pelophylax esculentus）这一杂种生殖型杂种（hybridogenetic hybrids）为研究对象：该类群由湖侧褶蛙（P. ridibundus）与池侧褶蛙（P. lessonae）杂交产生，但仅会将克隆型的湖侧褶蛙基因组传递至配子中。尽管食用侧褶蛙通常与池侧褶蛙交配，但当其与湖侧褶蛙或另一杂种个体交配时，可产生可进行有性生殖的湖侧褶蛙后代，其基因组携带渐渗自前克隆的外源片段。我们对比了两类种群的核扩增片段长度多态性（amplified fragment length polymorphism, AFLP）与线粒体渐渗速率，即包含……