It has long been assumed that interspecific hybridization and introgression (the transfer of genes from one species to the gene pool of another by backcrossing), in other words, reticular processes, play a very limited role in evolution and the acquisition of adaptations in mammals. Using the example of rodents endemic and inhabiting various mountainous habitats of the Ethiopian Highlands, the staff of the Laboratory of Mammal Microevolution of the IEE RAS, together with colleagues from the Institute of Vertebrate Biology of the Czech Academy of Sciences, managed to obtain evidence that interspecific hybridization and introgression between closely related mammalian species can lead to significant evolutionary consequences. Phylogenetic relationships of all nine Ethiopian species of speckled rough-haired mice Lophuromys flavopunctatus s.l. from geographic localities covering most of their distribution areas were studied using genomic methods. The results of the study revealed a significant discrepancy between mitochondrial and nuclear phylogenies resulting from ancient and recent interspecific hybridization events. Based on the data obtained, a scenario of the evolutionary history of this group is proposed, according to which modern species and their genetic diversity were formed as a result of a complex combination of divergent and reticular processes. It has been suggested that the introgression of the mitochondrial genome of a species inhabiting low altitudes (L. menageshae), pre-adapted to successful functioning in the harsh conditions of high mountains, was important in the development of high-mountain habitats (Afro-Alpine zone) by two other species (L. simensis and L. melanonyx ). The authors believe that further studies using high-throughput sequencing methods will provide a unique opportunity to study both the possible adaptive nature of the observed introgression and the mechanisms of co-evolution of mitochondrial and nuclear genes encoding proteins of the cellular respiration apparatus.
The work was carried out within the framework of the joint Russian-Czech project (RFBR no. 19-54-26003, Czech Scientific Foundation no. 20-07091J)
Original publication:
Komarova V.A., Kostin D.S., Bryja J., Mikula O., Bryjová A., Čížková D., Šumbera R., Meheretu Y., Lavrenchenko L.A., 2021. Complex reticulate evolution of speckled brush‐furred rats (Lophuromys) in the Ethiopian centre of endemism. Molecular Ecology, 30(10): 2349-2365.
Link to article: https://doi.org/10.1111/mec.15891