A novel selection signature in stearoyl-coenzyme A desaturase (SCD) gene for enhanced milk fat content in Bubalus bubalis

Modern molecular interventions are dynamic gears for breeding animals with superior genetic make-up. These scientific efforts lead us toward sustainable dairy herds with improved milk production in terms of yield and quality. Many of candidate genes have been dissected at molecular level, and suitable genetic markers have been identified in cattle, but this work has not been validated in buffaloes so far. Stearoyl-coenzyme A desaturase (SCD) has been a potential candidate gene for fat content of milk. Genomic analysis of SCD revealed a total of six variations that were identified through DNA sequencing of animals with lower and higher butter fat %age. After statistical analysis, genotype AB of p.K158I could be associated (P value < 0.0001) with higher milk fat %age (10.5 +/- 0.5464). This SNP was validated on larger data set by cleaved amplified polymorphic sequences (CAPS) by using DdeI. To scrutinize the functional consequences of p.K158I, 3D protein structure of SCD was predicted by homology modeling and this variation was found located in the vicinity of functional domain and a part of transmembrane helix of this membrane integrated protein. This is a first report toward genetic screening of SCD gene at molecular level in buffalo. This report illustrates the implication of SCD gene and in particular p.K158I variation, in imparting its effect on milk fat %age, which can be targeted in selection of superior dairy buffaloes.