In our previous studies, the evolutionary rate (substitutions/site/million years) of mitochondrial DNA (mtDNA) in rodents and moles was estimated to be approximately 0.11 in more recent divergence times of a few tens of thousands of years and declined quickly to approximately 0.03 in more distant divergence times. However, the modes and mechanisms associated with the time dependency have not been well documented. We addressed the abundance of nonsynonymous substitutions that had appeared in the protein-coding...