Relationship between substitution rate and life-history traits. a) Body mass (log transformed and in grams), b) Maximum longevity (log transformed and in years). Open circles and dotted regression line are for mammals (n = 500), close circles and solid regression line for birds (n = 196). Substitution rates are log transformed and are in unit of substitution per third codon position per million years.
Nabholz et al. BMC Evolutionary Biology 2009 9:54 doi:10.1186/1471-2148-9-54