Oxidative phosphorylation gene transcription in whitefish species pairs reveals patterns of parallel and non-parallel physiological divergence

Across multiple lakes in North America, lake whitefish (Coregonus clupeaformis) have independently evolved “dwarf” and “normal” sympatric species pairs that exhibit pronounced phenotypic and genetic divergence. In particular, traits associated with metabolism have been shown to be highly differentiated between whitefish species. Here, we examine the transcription of genes associated with all five mitochondrial and nuclear genome-encoded oxidative phosphorylation (OXPHOS) complexes, the primary physiological mechanism responsible for the production of ATP, in whitefish species pairs from Cliff Lake and Webster Lake in Maine, USA. We observed OXPHOS gene transcription divergence between dwarf and normal whitefish in each of the two lakes, with the former exhibiting transcription upregulation for genes associated with each of the OXPHOS complexes. We also observed a significant influence of lake on transcription levels for some of the genes, indicating that inter-lake ecological or genetic...