Figure 7From: The erratic mitochondrial clock: variations of mutation rate, not population size, affect mtDNA diversity across birds and mammalsmtDNA synonymous diversity ( π s ) and substitution rate. Open circles and dotted regression line are for mammals (n = 123), close circles and solid regression line for birds (n = 46). Substitution rates are in log-transformed and are in unit of substitution per third codon position per million years.Back to article page