The Genetic Mechanisms and Processes Driving Mitonuclear Coevolution in Admixed Populations

Mitochondrial function is essential to fitness but is dependent upon proteins encoded in the nuclear and mitochondrial genomes interacting efficiently within respiratory complexes. Mitonuclear incompatibilities, associated with decreased fitness, can arise when these two genomes, with separate modes of inheritance and mutation rates, encode for "mismatched" proteins. Large differences are known to lead to speciation, however milder intra-species effects, generated through widespread admixture events, are much less well understood, especially in natural populations. Computational population genetics techniques will be used to identify coevolving mitochondrial and nuclear gene pairs in naturally admixed modern Latin American populations, allowing for novel insight into the loci driving coevolution across broad timescales. Experimental evolution techniques will be used to simulate an admixture event in Drosophila melanogaster; this will allow us to track changes in mitonuclear coevolution directly through time and identify generalities of the coevolutionary process. Mitonuclear signatures will be compared across species and populations to help identify trends in the underlying processes driving coevolution and the potential consequences for vulnerable populations in the future. This will further be considered in the light of environmental temperature, known to be a key selective pressure on mitochondrial fitness.