The distribution of Gc subtypes among the mongoloid populations.

The polymorphism of Gc (group-specific components) has been investigated for a series of 3,160 individual samples from 11 Mongoloid populations in Asia and North and South America by isoelectric focusing on polyacrylamide gels. The samples fall into six Gc phenotypes which can be explained by the three common alleles, Gc1F, Gc1S, and Gc2, together with several variant phenotypes explained as the heterozygotes for the three common alleles. The distribution of Gc1F suballele appears to be considerably different from population to population among Mongoloids, ranging from 0.105 (Machiguenga Indians, Peru) to 0.609 (Kadazan, Borneo). A clear geographic cline from Southeast Asia into South America in Gc1F allele was observed in the populations. In general, Gc1F allele frequencies are lower in European populations and higher in African populations. The range of variability in the Gc1F values observed among the Asiatic populations is between the Africans and the Europeans.