Gametogenesis produces gametes as a piece of genetic information transmitted to the offspring. While during sexual reproduction, progeny inherits a mix of genetic material from both parents, asexually reproducing organisms transfer a copy of maternal or paternal DNA to the progeny clonally. Parthenogenetic, gynogenetic and hybridogenetic animals have developed various mechanisms of gametogenesis, however, their inheritance is not fully understood. Here, we focused on the inheritance of asexual gametogenesis in hybrid Pelophylax esculentus (RL), emerging after crosses of P. lessonae (LL) and P. ridibundus (RR). To understand the mechanisms of gametogenesis in hybrids, we performed three-generation experiments of sexual P. ridibundus females and hybrids from all-male hybrid populations. Using fluorescent in situ hybridization, micronuclei analysis, flow cytometry and genotyping, we found that most adult hybrid males simultaneously produced two types of clonal sperm. Also, most male tadpole progeny in two successive backcrossed generations simultaneously eliminated L and R parental genomes, while some progeny produced only one type of sperm. We hypothesize that the reproductive variability of males producing two kinds of sperm is an adaptive mechanism to reproduce in mixed populations with P. ridibundus and may explain the extensive distribution of the all-male lineage across the European River Basin.

Department of Biology and Ecology Faculty of Science University of Ostrava Chittussiho 10 Ostrava 710 00 Czech Republic

Institute of Animal Physiology and Genetics Laboratory of Fish Genetics The Czech Academy of Sciences Liběchov 277 21 Czech Republic

Institute of Animal Physiology and Genetics Laboratory of NonMendelian Evolution The Czech Academy of Sciences Liběchov 277 21 Czech Republic

Laboratory of Amphibian Population Ecology Department of Zoology and Animal Ecology School of Biology 5 N Karazin Kharkiv National University Kharkiv Ukraine

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