The enzyme serum paraoxonase shows a polymorphism in Europeans which is governed by two alleles. The first allele has a gene frequency plow of 0.716-0.777, and is manifested as a low activity group in homozygotes. More than 50% of all European test subjects can be included in this group. A second allele with a gene frequency ghi& of 0.223-0.284 was found in typical European distributions and is manifested in both the form of a second heterozygotic and a third homozygotic group with high activities. The Hardy-Weinberg rule for a two-allele model is valid for the distribution. The gene frequency plow of the first allele decreases as one moves from Europe in the direction of Africa and Asia. In typical Mongoloid and Negroid collectives, less than 10% of the population can be included in the low-activity group, a group which is not even demonstrable in the Aborigines of Australia. The serum paraoxonase of the Aborigine population shows unimodal distribution.
The validity of the Hardy-Weinberg rule for a three-allele model must be rejected in all examined collectives. Human serum paraoxonase shows neither age-related changes in activity nor sex-dependent activity differences.