Difference between the Hb C variants in Brahman and in indigenous Southern African cattle breeds

Summary Haemoglobin polymorphism in Brahman cattle and seven Southern African cattle breeds was investigated by means of starch gel electrophoresis. A difference was found between the migration rates of the Hb C of Brahman cattle and that of the indigenous Southern African cattle breeds, showing that these are actually two separate variants. We suggest that the faster migrating type, which occurs in Brahman cattle, should be called Hb C, while the slower migrating type of the Southern African breeds, should be called Hb I. A comparison of the migration of the α and β chains of all the variants we encountered, including foetal haemoglobin, was carried out by means of starch gel electrophoresis in urea at acid and alkaline pH levels. Evidence was found of a difference in mobility of the non-a chains of haemoglobin A, B, C, I and F at different pH levels while no difference was detected in the migration rate of their respective α chains. These results confirm the theory that genetic variation is restricted to the non-α chain of bovine haemoglobin. Progeny studies on 225 families confirm that the Hb I variant is allelic to Hb A and Hb B variants. The gene frequencies have been calculated on the basis that Hb I and Hb C are allelic at the β locus. The distribution of the different phenotypes is in accordance with this theory, assuming that the populations obey Hardy-Weinberg equilibrium.