Nonsynonymous substitution rate (dN) and synonymous substitution rate (dS) of the three domains in the MRFs.

<p><b>A</b>), <b>B</b>) and <b>C</b>) represent the dN/dS differences of the three domains of the MRFs in vertebrates, mammals and <i>Myf5</i> genes, respectively. <b>D</b>), <b>E</b>) and <b>F</b>) represent the dN/dS differences of the four MRFs genes in their HLH, BASIC and MYF5 domains, respectively.