Genetics of caseins in domestic ruminants

Milk caseins are the major protein source for the newborn, providing amino acids that are essential to sustain growth as well as peptides with immunomodulatory activities. Caseins have also a remarkable impact on the dairy industry, being the main determinant of the efficiency with which milk is transformed into cheese. Casein genes have been thoroughly studied in cattle, sheep and goats, allowing for the stablishment of to causal relationships between their polymorphism and milk composition. In cattle, polymorphism in the β-casein (CSN2) and κ-casein (CSN3) gene has been reported to have effects on the composition and rheological properties of milk. Similarly, the variability of the goat αS1- casein (CSN1S1) gene has been shown to determine the synthesis rate of this protein as well as to have effects, at least in certain breeds, on milk composition and cheese yield and organoleptic properties. Even more, the caprine CSN3 gene has been associated with milk protein and casein levels. These findings confirm domestic ruminants as a unique model to elucidate the genetic factors that modulate the amount of synthesized caseins and milk composition. © 2012 Nova Science Publishers, Inc. All rights reserved.