Myogenin (MyoG) is a vital member of the myogenic regulatory factors (MRFs), and plays an essential role in regulating myocyte development and maturity. , one of the most economically important fish in China, displays sexual dimorphism in both size and growth. To characterize the , we cloned the full-length cDNA of this species with reverse transcription-PCR and the rapid amplification of cDNA ends. The cDNA included a 63-bp complete 5' untranslated region (5'-UTR), a 521-bp 3'-UTR, and a 762-bp open reading frame encoding a 253-amino-acid peptide containing a basic arginine-rich domain and the helix-loop-helix structural domain typical of MRFs. The amino acid sequence was more similar to that of (94.1%) than to those of other species. A phylogenetic analysis based on amino acid sequences showed that I. furcatus, and of the Siluriformes. These results indicate a high degree of conservation during gene evolution. An expression analysis of MyoG in the heart, brain, liver, kidney, muscle, stomach, intestine, and gill showed that it is only significantly highly expressed in muscle tissue ( < 0.05). Western blot analysis demonstrated that MyoG protein expression was higher in males than in females. We infer that MyoG plays an important role in the muscle development and growth of male and female based on its expression characteristics at the gene and protein levels. These results extend our understanding of MyoG function, clarify the growth and differentiation of male and female P. fulvidraco strains.