K-casein B

Genetic variants of k-casein

There are several genetic variants (alleles) of k-casein and their presence in cow milk depends on those present on the DNA of the subject.
The different variants of k-casein are reported in the figure below. Differences among variants concern the substitution of 1-2 amino acids. For example, A and B variants differ for two amino acids.
However, these few differences lead to marked differences at the dairy level for milk.
A and B are largely the wide diffused variants among cattle breeds.

MILK PROTEIN POLYMORPHISM: DETECTION AND DIFFUSION OF THE GENETIC VARIANTS IN BOS GENUS