Chicken Mx gene polymorphisms in Indian native chicken breeds and White Leghorn by real time multiplex allele specific PCR

Abstract

Chicken Mx protein confers resistance against viral infections including avian influenza virus. Mx protein is one of the strong antiviral proteins induced by interferon system. Different alleles of chicken Mx gene have been shown to vary in their antiviral activity against influenza virus. A non-synonymous mutation at position 2032 of chicken Mx gene responsible for variation of amino acid (Ser to Asn) in Mx protein is responsible for negative to positive antiviral activity of Mx protein.In the present study it was analyzed that SNP at G2032A in chicken Mx gene in two Indian native chicken breeds, Aseel, Kadaknath and compared with White Leghorn layer. A total of 90 samples, including 50 of White Leghorn and 20 each from native chicken breed were screened for SNP at position 2032 of Mx gene by using real time multiplex allele specific PCR. The resistant allele (A) frequency is higher than susceptible allele in all three chicken breeds investigated. Among the breeds, the resistant allele frequency (A) is higher in White Leghorn (0.95) followed by Aseel (0.75) and Kadaknath (0.625). Homozygous to resistant allele (AA) is the major genotype in White Leghorn whereas heterozygous to both alleles is the major genotype in Kadaknath. Variations in the gene frequency might have emerged from varying degree of selection pressure the different breeds had undergone. In future, the resistant genotype could be selected in modern breeding programs to improve the genetic status for disease resistance against viral infections.

Pathobiology of the highly pathogenic avian influenza viruses H7N1 and H5N8 in different chicken breeds and role of Mx 2032 G/A polymorphism in infection outcome

“…In contrast, the results in local breeds were more variable, which could be associated with the higher genetic diversity generally present in unselected breeds. Overall, the susceptible G allele prevails in the Spanish chickens tested, while the resistant A allele was the predominant in two Indian native chicken breeds [54], a native chicken breed from Indonesia [55] and 2 chicken breeds and 7 strains from Egypt [56]. The statistical analyses showed that the different genotypes in the target Mx region were not associated with significant differences in mortality ratios.…”

Polymorphisms of the Chicken Mx Gene Promoter and Association with Chicken Embryos’ Susceptibility to Virulent Newcastle Disease Virus Challenge

“…The genomic size of the chicken Mx gene is about 21 kbps with the coding sequences of about 2118 bps encoding the Mx protein comprising 705 amino acids [4, 5]. Like other IFN-response genes, the chicken Mx gene contains a sequence element in its promoters that serve as inducible enhancers.…”