Convergent evolution of genes controlling mitonuclear balance in annual fishes

Complexes of the respiratory chain are formed in a complex process where nuclearly-and mitochondrially-encoded components are assembled and inserted into the inner mitochondrial membrane. The coordination of this process is named mitonuclear balance and experimental manipulations of mitonuclear balance can increase longevity of laboratory species. Here, we investigated the pattern of positive selection in annual (i.e. short-lived)and non-annual (i.e. long-lived) African killifishes to identify a genomic substrate for evolution of annual life history (and reduced lifespan). We identified genes under positive selection in all mitonuclear balance: mitochondrial (mt) DNA replication, transcription from mt promoters, processing and stabilization of mt RNAs, mt translation, assembly of respiratory chain complexes and electron transport chain. Signs of convergent evolution are observed in four out of five steps. This strongly indicates that these genes are preferential genetic targets for the evolution of short lifespan and annual life cycle