Aspartic acid codon 385 (GAC) in exon 3 was changed to glycine (GGC) (p.D385G) and glutamine codon 387 (CAG) to glutamic acid (GAG) (p.Q387E) using an sgRNA and an ssODN template with CRISPR/Cas9 technology. The mutations change the endogenous amino acids in the encoded peptide to their equivalents from paralog Mstn. (J:342779)