Figure 5From: Next generation sequencing and comparative analyses of Xenopus mitogenomesRatios of nonsynonymous/synonymous (dN/dS) nucleotide substitutions between the protein-coding genes of xenopus mitochondrial genomes. Although the ratios differ considerably between genes, complexes and pairs of species, in all cases genes are evolving under negative (purifying) selective pressure (dN/dS < 1).Back to article page