Positive and relaxed selection on mitochondrial DNA in parasitic versus predatory mites

Abstract Mitochondrial genomes (mtDNA) have distinct evolutionary trajectories owing to their inheritance, ploidy and underlying mutation rates, making them prone to accumulate slightly deleterious mutations. Positive selection on mtDNA has been suggested to be important during adaptation to ‘high-energy’ lifestyles and environments. Disentangling positive versus relaxed selection in molecular mtDNA evolution studies is therefore important, although common metrics such as elevated dN/dS ratios (