DGAT1 (acyl-CoA:diacylglycerol acyltransferase) gene encodes the microsomal enzyme diacylglycerol O-acyltransferase. This enzyme catalyzes the final step of triglyceride synthesis and plays a fundamental role in the metabolism of cellular diacylglycerol in different physiological processes, such as intestinal fat absorption, lipoprotein assembly and adipose tissue formation.
A non-conservative lysine (K) to alanine (A) substitution has been identified at position 232 (K232A polymorphism), as a consequence of an AA to GC nucleotide substitution at position 10433 and 10434 of DGAT1 exon VIII. A significant decrease in protein and milk yields and an increase in fat yield are associated with the lysine variant (K allele). The alanine substitution (A allele) is associated with an increase in protein and milk yields, and a decrease in fat yield, due to a deficient triglyceride synthesis in the mammary gland.