Polymorphic characterisation of gallinacin candidate genes and their molecular associations with growth and immunity traits in chickens.

1.Four gallinacin () genes were assessed by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) to characterise these genes in Fayoumi (F) and Rhode Island Red (R) breeds and their crosses of Rhode Island Red Fayoumi (½R½F) and Fayoumi Rhode Island Red (½F½R).2.Genes examined were and . The molecular associations between the SNPs of the gallinacin genes and body weight, caecal bacterial count and the serum antibody titres of IgA, IgG and IgM were determined. In the R breed, the frequency of TC genotype was higher than TT and CC genotypes for the gene. The GG genotype frequency was higher than AA and AG genotypes for the gene in the other genetic groups, and the CA genotype frequency was higher than CC and AA genotypes in crosses for the gene.3.In all populations, the frequency of the C allele was higher than the T allele for the gene, the G allele was higher than the A allele for the gene and the C allele was higher than the A allele for the gene. The observed heterozygosity in R, ½R½F and ½F½R was 0.476, 0.375 and 0.158 for the gene, 0.458, 0.615 and 0.250 for the gene and 0.053, 0.792 and 0.739 for the gene, while the expected heterozygosities were 0.490, 0.430 and 0.145 for the gene, 0.430, 0.348 and 0.219 for the gene and 0.229, 0.478 and 0.496 for the gene, respectively.4.On a molecular level, the genotype TT was significantly higher for body weight than TC and CC genotypes in the gene. Birds with the GG genotype had a significantly lower count than birds with AA genotype in the gene. Birds with the genotype AA had higher significant body weights than those with CC and CA genotypes in the 5 gene.5.The results indicated that the and genes are potential candidates for selection programmes to improve resistance and body weight in chickens.