The mutation rates are involved in a myriad of evolutionary phenomena, including the maintenance of sex and rates of molecular evolution.
Although there is substantial evidence that mutation rates vary among taxa, relatively little is known about the factors that underlie this variation at an empirical level, particularly in multicellular eukaryotes.
See also
Mutations
References
Baer CF, Miyamoto MM, Denver DR. Mutation rate variation in multicellular eukaryotes: causes and consequences. Nat Rev Genet. 2007 Aug;8(8):619-31. PMID: 17637734