Human mitochondrial DNA has been estimated to have mutation rates of ~3× or ~2.7×10 −5 per base per 20 year generation (depending on the method of estimation); these rates are considered to be significantly higher than rates of human genomic mutation at ~2.5×10 −8 per base per generation.he highest per base pair per generation mutation rates are found in viruses, which can have either RNA or DNA genomes. DNA viruses have mutation rates between 10 −6 to 10 −8 mutations per base per generation, and RNA viruses have mutation rates between 10 −3 to 10 −5 per base per generation.