Analysis of the Gc polymorphism in human populations by isoelectrofocusing on polyacrylamide gels. Demonstration of subtypes of the Gc1 allele and of additional Gc variants

For the study of the group-specific component (Gc) system, serum samples were examined by polyacrylamide gel electrophoresis and by a newly developed immunofixation isoelectrofocusing procedure. Thereby, a greater extent of polymorphic variation was revealed than was known previously. The allele Gc1 could be subdivided into the alleles Gc1F and Gc1S. The distribution of Gc1 subtypes was very different in three populations (Pygmies, Amerindians, and Pyreneans) examined. New variants of the Gc1 and Gc2 genes were also described in the Amerindian and in the Pygmy population, respectively.