Population genomics of an exceptional hybridogenetic system of Pelophylax water frogs

Hybridogenesis can represent the first stage towards hybrid speciation where the hybrid taxon eventually weans off its parental species. In hybridogenetic water frogs, the hybrid Pelophylax kl. esculentus (genomes RL) usually eliminates one genome from its germline and relies on its parental species...

Full description

Saved in:

Bibliographic Details
Published in:	BMC evolutionary biology Vol. 19; no. 1; p. 164
Main Authors:	Dubey, Sylvain, Maddalena, Tiziano, Bonny, Laura, Jeffries, Daniel L, Dufresnes, Christophe
Format:	Journal Article
Language:	English
Published:	England BioMed Central Ltd 05-08-2019 BioMed Central BMC
Subjects:	Amphibians Animals Chromosomes Distribution Female Genetic aspects Genetic research Genetic Speciation Genome Genomes Genomics Germ Cells Heterozygote Hybrid amphigamy Hybrid amphispermy Hybrid animals Hybrid speciation Hybridization, Genetic Male Myobatrachidae Natural history P. lessonae Pelophylax kl. esculentus Phylogeography Ranidae - classification Ranidae - genetics Reproduction Reproductive Isolation Sperm Switzerland Triploidy Water Switzerland Hybrid speciation Sex chromosomes Hybrid amphispermy RAD-sequencing Hybrid amphigamy Pelophylax kl. esculentus Polyploidization P. lessonae Amphibians Water frogs
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Hybridogenesis can represent the first stage towards hybrid speciation where the hybrid taxon eventually weans off its parental species. In hybridogenetic water frogs, the hybrid Pelophylax kl. esculentus (genomes RL) usually eliminates one genome from its germline and relies on its parental species P. lessonae (genomes LL) or P. ridibundus (genomes RR) to perpetuate in so-called L-E and R-E systems. But not exclusively: some all-hybrid populations (E-E system) bypass the need for their parental species and fulfill their sexual cycle via triploid hybrid frogs. Genetic surveys are essential to understand the great diversity of these hybridogenetic dynamics and their evolution. Here we conducted such study using RAD-sequencing on Pelophylax from southern Switzerland (Ticino), a geographically-isolated region featuring different assemblages of parental P. lessonae and hybrid P. kl. esculentus. We found two types of hybridogenetic systems in Ticino: an L-E system in northern populations and a presumably all-hybrid E-E system in the closely-related southern populations, where P. lessonae was not detected. In the latter, we did not find evidence for triploid individuals from the population genomic data, but identified a few P. ridibundus (RR) as offspring from interhybrid crosses (LR × LR). Assuming P. lessonae is truly absent from southern Ticino, the putative maintenance of all-hybrid populations without triploid individuals would require an unusual lability of genome elimination, namely that P. kl. esculentus from both sexes are capable of producing gametes with either L or R genomes. This could be achieved by the co-existence of L- and R- eliminating lineages or by "hybrid amphigamy", i. e. males and females producing sperm and eggs among which both genomes are represented. These hypotheses imply that polyploidy is not the exclusive evolutionary pathway for hybrids to become reproductively independent, and challenge the classical view that hybridogenetic taxa are necessarily sexual parasites.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1471-2148 1471-2148
DOI:	10.1186/s12862-019-1482-4