Absence of Relationship between Mitochondrial DNA Evolutionary Rate and Longevity in Mammals except for CYTB

Abstract

On the relationship between mitochondrion and longevity in mammals, two viewpoints have been proposed: one found that the amino acid substitution rates of most of the mitochondrial DNA-coding peptides were positively correlated with longevity, while the other raised the opposite view. To resolve this dichotomy, and to explore the relationship between mtDNA evolution and longevity in mammals, we examined this relationship in 85 mammal species, at the nucleotide sequence level. Previous studies have demonstrated that phylogenetic inertia, substitution saturation, and body mass can affect the relationship between longevity and substitution rate. Therefore, analyses should take these factors into account. This study found that after controlling the aforementioned factors, no significant positive or negative relationship existed between mitochondrial DNA evolutionary rate and longevity except for CYTB, partly agreeing with a previous study. Variations of longevity can be explained partly by the evolutionary rate of CYTB, but other influencing factors still need to be studied in the future.