Hybridogenesis in Water Frogs

esculentus (mostly RL genome), which is a hybridogenetic hybrid of the marsh frog P. ridibundus (RR) and the pool frog P. lessonae (LL), usually excludes the lessonae genome (L) and generates gametes of the P. ridibundus (R). Their mating patterns are classified into several hybridogenetic systems:[2]

All these hybrids contain genome of marsh frog P. ridibundus (R) and genome of second parental species (L, P or B). esculentus (genotype RL) exclude here the P. ridibundus (R) or P. lessonae (L) genome in a 3:1 ratio and make mainly clonal P. lessonae (L), less P. ridibundus gametes (R).

Source: en.wikipedia.org