Kravchenko et al., 2018. Hemiclonal Inheritance in Water Frogs: A Random Curiosity, a Transitional State, or a Regular Stage of Evolution?

HEMICLONAL INHERITANCE IN WATER FROGS: A RANDOM CURIOSITY, A TRANSITIONAL STATE, OR A REGULAR STAGE OF EVOLUTION? Kravchenko M., Pustovalova E., Fedorova A., Shabanov D. V. N. Karazin Kharkiv National University e-mail: marinakravchenko2106[]gmail.com, shabanov[]karazin.ua M. Kravchenco, E. Pustovalova, A. Fedorova, D. Shabanov. HEMICLONAL INHERITANCE OF WATER FROGS: OCCASIONAL INCIDENT, TRANSITION STATE OR THE NATURAL STAGE OF DEVELOPMENT? We propose hypothesis that defines hemiclonal inheritance as a rare natural evolutional way to overcome interspecies hybrid sterility (as well as clonality and polyploidy). The main consequences of hemiclonal inheritance are clonal evolution of genomes and homological interspecies recombination. On the example of hybridogenic Pelophylax esculentus complex we discuss possible reasons and steps of evolution of hemiclonal population systems (HPS). We also discuss unique types of HPS that are typical for the Siverskyi Donets center of diversity of water frogs. Keywords: Pelophylax esculentus complex, hibridogenesys, hemiclonal population systems, recombination, multilevel selection. Hemiclonal inheritance in water frogs (Fig. 1) is often regarded as a certain stage in the formation of a hybrid tetraploid species [1]. Thus, in water toads, triploidy can be both an accidental occurrence and a stage in the emergence of hybrid species [6]. Unlike toads, population systems of water frogs containing triploids regularly arise in many parts of the range [7] and are capable of stable and long-term existence [3, 4]. We consider hemiclonality as a regular (though rare) way of overcoming the sterility of interspecific hybrids (Fig. 2). We propose a hypothesis regarding the pathway of origin of this phenomenon and the nature of the selection that sustains it (Fig. 2, 3). Fig. 1. Hemiclonal reproduction of interspecific hybrids of water frogs and typical HPS in the Siverskyi Donets center of their diversity Fig. 2. Probable mechanism of the origin of hemiclonal inheritance Fig. 3. Probable stages of HPS evolution in water frogs The results of hemiclonal inheritance include clonal genome evolution, one consequence of which is the phenomenon of hybrid amphigamety (= hybrid amphispermy) [2, 4], as well as homologous interspecific recombination between parental species. Borkin L. Ya., Darevsky I. S. Reticulate (hybridogenous) speciation in vertebrates // Zh. obshch. biol. 1980.

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