Identification of functional consequence of a novel selection signature in CYP11b1 gene for milk fat content in Bubalus bubalis

Abstract

Genomic selection for traits of economic importance is an emerging approach carrying tremendous potentials. Many of polygenic traits as milk fat, protein and yield have been characterize at genomic level and important selection signatures have been identified. Cytochrome P450 enzymes are potential loci for affecting many of dairy capabilities. Present study was conducted for genomic dissection of CYP11b1 gene in riverine buffaloes and seven genetic variations were identified. Out of these, one novel polymorphism (p.A313T) was found well associated with milk fat %age. AB genotyped buffaloes were found to have higher milk fat %age (8.9%) for this loci. p.A313T was further validated at larger data set by restriction digestion using CviAII enzyme. Functional consequences of this locus were also predicted by studying three dimensional structure of CYP11b1 protein. For this purpose, 3D protein model was predicted by homology modeling, secondary structural attributes were determined, signal peptide was predicted and a transmembrane helix was also identified. One of polymorphism (p.Y205L) was found in the vicinity of functionally significant F-G loop region, which is the part of protein gets attached to the inner mitochondrial membrane. But this variation could not be associated and needs further investigation. p.A30V, a popular selection marker in cattle, was found in buffaloes as well but could not be associated and might need further confirmation on larger data set. Results of this study illustrate the impending potential of this gene in determining dairy capabilities of buffaloes and might have a role in selection of superior dairy buffaloes.