Nucleotide substitution rates in sex-bias genes per tissue. Mean values with 95% confidence intervals for rate of nucleotide substitutions in coding sequences. (A) d
ratios; (B) d
; and (C) d
. Male-biased (MB: blue), female-biased (FB: pink), and unbiased (UB: yellow) genes for brain, gonad, and tail. Asterisks above the boxplots indicate a significant difference in substitution rate was found between the sex-biased and unbiased genes using Mann–Whitney U test for non-parametric distributions (**** p < 0.0001; *** p < 0.001; ** p <0.01; * p < 0.05).