Milk casein polymorphism in man.

Urea-starch-gel electrophoresis was used to examine 175 casein samples, 130 collected at random from women from the urban area of Turin, and 45 from women resident in villages in the Sardinian hinterland. Two polymorphic systems controlling alpha- and beta-casein were demonstrated in both groups, together with similar gene frequencies for individual alleles. In addition, a rare variant was discovered in the Sardinian group.