Genetic polymorphism in BLB2 region among guinea fowl and other poultry species

Genetic polymorphism in β₁, domain of BLB2 gene between guinea fowl and other poultry species through sequence homology comparisons was studied. A 277 bp amplicon representing exon 2 corresponding to β₁ extra cellular domain of BLB2 gene was amplified in guinea fowl as well as in chicken. Sequence homology comparisons of the 277 bp sequence of guinea fowl and chicken showed a total of 28 nucleotide substitutions (15 transitions plus 13 transversions). Guinea fowl showed maximum per cent identity (88.8) with chicken, followed by quail (79.4), turkey (75.1) and pheasant (74.3), while ducks showed least per cent identity (63.9). Lower nucleotide sequence as well as higher rate of transitions suggest the higher structural and functional similarity in β₁ domain of guinea fowl and chicken, which is functionally very important being the part of peptide binding region of class II antigen. Phylogenetically, guinea fowl and chicken are clustered together in one sub-cluster, while turkey and quail in another sub cluster. Duck is totally clustered out making a separate branch.