Relationship between substitution rate and life-history traits. a) Relationship with body mass (log transformed and in grams), b) Relationship with maximum longevity (log transformed and in years). Circles are for passerine birds (n = 88), triangles for non-passerine birds (n = 108). 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