Molecular evolutionary analysis of the duck MYOD gene family and its differential expression pattern in breast muscle development.

1. The objective of the research was to investigate the molecular evolutionary relationships between the duck myogenic determination factors (MYOD) gene family members and their roles in muscle development. 2. The four members of the duck MYOD gene family were cloned using RT-PCR, and their relative mRNA expression during duck muscle development was measured using qRT-PCR. 3. The results showed that MyoD and Myf5 clustered together, as did MyoG and MRF4 based on their complete amino acid sequence and the basic helix-loop-helix domain. Results of the evolutionary level analysis were consistent with that of the differential expression patterns during duck breast muscle development. As determined by qRT-PCR, MyoD and Myf5 were highly expressed in 22-day embryos, while MyoG and MRF4 expression was high in 14-day embryos. 4. We conclude that the entire MYOD gene family in the duck originated from a common ancestral gene and evolved after two duplication events. The roles of the MYOD gene family members in duck muscle development are similar to those in mammals.