Casein Alpha (CSN1)

Milk casein can be separated by urea starch electrophoresis into 3 regions, alpha, beta, and kappa casein. Alpha and beta variants are present in the human population. In Italy the frequency of the 2 alpha alleles was 0.908 and 0.092; 2 beta alleles had a frequency of 0.678 and 0.322. the human alpha-S1, beta-, and kappa-casein genes are closely linked and arranged in that order. By fluorescence in situ hybridization, they demonstrated that the casein gene family is localized to 4q21.1. the human 'locus' comprises at least 4 casein genes: 3 genes encoding calcium-sensitive, casein-like genes, and 1 kappa-casein gene, in the order alpha-s1--beta--alpha-s2--kappa. The approximate size of the human casein gene locus is 350 kb. the casein cluster is located within 700 kb of the albumin gene cluster, which is located on 4q13.