Immunoglobulin constant heavy chain gene polymorphisms of Caucasoids of west European origin.

We have used restriction fragment length polymorphism (RFLP) analysis to investigate the immunoglobulin constant heavy chain (IgCH) loci and the associated locus Dl4Sl, of Caucasoids from South East England and South-West. West Germany, Haplotypes were determined using probes to the Ig heavy chain switch loci S mu and S alpha 1, the IgC gamma 3 and IgC gamma 2 loci as well as the Dl4Sl locus which is 3' of the IgCH loci. The 6.3:1.7 kilobase (kb) Bst EII C gamma 3-C gamma 2 haplotype was the most prevalent in the population from South-East England (frequency 0.364), whilst the 2.3:3.7 kb C gamma 3-C gamma 2 haplotype was the major haplotype in the German population (frequency 0.400). With one exception, the major haplotypes of these two populations differed from the ones previously published for a Caucasoid population from California. This suggests that there may be a major ancestral IgCH haplotype which has been maintained in the population, whilst other haplotypes tend to be specific for a particular group of Caucasoids.