Widespread distribution of variant forms of carbonic anhydrase in Australian aboriginals.

Three distinctive genes which control variants of carbonic anhydrase (CA) have been detected in tests on nearly 3000 Aboriginals from various parts of Australia. Two of these genes affect the products of the CA1 locus, the other affects the products of the CA2 locus. In some populations of Aboriginals, more than 10% of persons have a variant carbonic anhydrase. It is suggested that such an unusual frequency of CA variants may be an evolutionary response to metabolic stress connected either with low zinc concentrations in the diet or with the altered needs of ion regulation in an arid environment.