Mitochondrial-nuclear co-adaptation in European water frogs

• Applicants: Dr. Jörg Plötner; Dr. Albert J. Poustka
• Subject Area: Animal Physiology and Biochemistry
• Term: from 2012 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 212710783

European water frogs of the genus Pelophylax exhibit genetic peculiarities allowing a new and unique experimental approach to studying mitochondrial-nuclear (mitonuclear) interactions and co-adaptation. We intend to analyze the impact of mtDNA introgression on respiration (O2 consumption, CO2 production) using lake frogs (Pelophylax ridibundus) with native (ridibundus-specific) and introgressed mitochondrial genomes of P. lessonae. We will aim at answering the question whether the transfer of lessonae-specific mitochondrial genomes is linked to ecological adaptation of P. ridibundus in the northern part of its range. To assess the amount of asymmetric hybrid fitness caused by cytonuclear (including mitonuclear) incompatibilities we will perform reciprocal interspecies crosses and will determine viability, fertility, and metabolic rates of F1 individuals. Crosses between hybridogenetic P. esculentus that exclude the lessonae genome in their germ line and produce haploid gametes with an unrecombined ridibundus genome enable us to analyze the role individual differences in the nuclear genomes play for hybrid viability in the context of cytonuclear coadaptation. To understand the molecular nature of mitonuclear interactions we will sequence and analyze native and introgressed mitochondrial genomes isolated from P. lessonae, Central European P. ridibundus, Balkan P. kurtmuelleri, and hybridogenetic P. esculentus. To find nuclear genes that could play a role for mitonuclear coadaptation we intend to compare the transcriptome of P. ridibundus with the transcriptome of P. lessonae. We expect that the comparative analysis of mtDNA, respiratory, and ecological data will provide new insights useful to understanding the molecular nature and evolutionary significance of mitonuclear co-adaptation in water frogs as a model especially for ectothermic organisms.

• DFG Programme: Research Grants
• Participating Person: Dr. Stefan K. Hetz