Effects of

To meet up the demand gap of milk in Bangladesh, short-term, midterm, and long-term goal have been set up by the government through crossing with Bangladeshi local cattle and high-producing foreign cattle like Friesian, Jersey, Sahiwal, etc. The purpose of this study was to identify the single nucleotide polymorphisms (SNPs) in the FASN gene, to check the structural and functional impact of mutant proteins on milk production traits that are significantly associated. Four SNPs were identified in exons 26, 36, 38, and 41 of the FASN gene using pooled DNA sequencing, but only one SNP g.17924 A>G was a non-synonymous that changed the amino acid threonine to alanine in the FASN protein and the other three SNPs were silent mutations. Structural and functional prediction analysis were done with a series of techniques to detect remote protein homology and predict structures, structural integrity, structure quality, protein stability, protein motion, flexibility, and stability impact, conservation profile and finally molecular dynamics simulations for wild-type and mutant protein expression differences. The non-synonymous g.17924 A>G mutation showed a clear difference between wild and mutant proteins, indicating the impact on the observed phenotype. Then, SNP g.17924 A>G was genotyped in 100 milking cows aiming to check the association effects. SNP g.17924 A>G was found to have significant allele substitution effects on milk yield traits. Our results suggest that the identified polymorphism affects milk yield traits in the studied population and could be used as genetic marker for cattle selection processes aiming to increase productivity.