Average heterozygosity per locus in man: an estimate based on the incidence of enzyme polymorphisms

SUMMARY 1. Data from electrophoretic surveys of enzymes in European populations are reviewed. 2. Out of the seventy‐one structural gene loci determining enzyme structure which have been scrutinized electrophoretically, 20 (28 %) were found to show genetic polymorphism. The average heterozygosity per locus for alleles determining electrophoretic variants is estimated at 0·067. 3. These results are compared with data from some other species. 4. For several different reasons, most of which relate to the techniques used and the enzymes and tissues surveyed, it seems likely that the present data considerably underestimate the true incidence of polymorphism and average heterozygosity per locus.