Myxovirus (Mx) proteins are essential antiviral protein components induced by interferon in many species. This study aims to determine the genotype of 72 Javanese backyard waterfowl based on the Mx gene. Mx gene was amplified using PCRRFLP technique by primers NE-F2/F and NE-R2/R. The expected 100bp PCR product was visualized by 1.2% high-resolution MetaPhor™ Agarose. To determine the genotype of Mx gene, the PCR fragment was cut by RsaI. The results showed that all Mx-- samples generated 73bp and 27bp fragments, indicating that all waterfowl species were (GG genotype) and showed susceptibility to the avian influenza virus infection. The susceptible species are difficult to be identified based on its morphological appearance since waterfowl do not show any symptoms of illness. Therefore, Mx gene genotyping has the potential for breed selection to obtain healthy and resistant waterfowl both phenotype and genotype. Targeting the Mx gene is a potential approach for the development of avian influenza-resistant poultry
