Could 4‐beta‐galactosyltransferase have a function in sexual precocity in bulls?

Theglycoprotein‐N‐acetylgalactosamine 4‐beta‐galactosyltransferase catalyzes the chemical reaction UDP‐galactose + glycoprotein N‐acetyl‐D‐galactosamine ⇌ UDP + glycoprotein D‐galactosyl‐1,3‐N‐acetyl‐D‐galactosamine. Its gene has a polymorphism at nucleotide 174 that results on the substitution of arginine (AGG) for lysine (AAG). This gene is involved on scrotal growth. Currently, animals with larger scrotal circumference are chosen to be used as breeders. We decided to investigate whether the gene b4galt1 polymorphism is related to sexual precocity in cattle breeds in Nellore and Gir, and thus prove the enzyme's role in that area too. 234 bulls were divided into groups according to their breed and their DEP (expected progeny difference) for scrotal circumference at 455 days. Their genomic DNA were extracted and a fragment of 524 bp was amplified by PCR using primers to the region of B4galt1 of interest. Subsequently, analysis of polymorphism was performed by Restriction Fragment Length Polymorphism with restriction enzyme Nco I. In both bulls examined, only the presence of the aminoacid lysine was identified, which is encoded by the presence of allele A. Maybe a greater number of animals could explore better the other function of b4galt1 enzyme. With these data confirmed, it will be possible to use this polymorphism as a molecular marker for genetic selection in Nellore and Gir cattle.