title: Gene organization of haplotypes expressing two different C4A allotypes.
abstract: The gene organization of C4 haplotypes expressing two different C4A allotypes with a C4B null allele (C4A3A2BQ0 and C4A3A6BQO) was studied using Southern blot analysis with cDNA probes and restriction enzymes which give C4A and C4B locus-specific restriction fragments. These haplotypes were shown to have both a C4A and a C4B locus present, suggesting that the C4B locus expresses a C4A protein. The finding of a 21-OH A and a 21-OH B gene on the C4A3A6BQO haplotype further suggests that this haplotype has the common gene organization C4A, 21-OH A, C4B, 21-OH B. A model explaining C4 null alleles on haplotypes found to have two C4 loci is presented.
mesh_terms: D000483:Alleles; D003181:Complement C4 / Q000235:genetics*; D015934:Complement C4a; D015935:Complement C4b; D004247:DNA / Q000235:genetics; D004262:DNA Restriction Enzymes; D005260:Female; D005785:Gene Conversion; D008040:Genetic Linkage; D006680:HLA Antigens / Q000235:genetics; D006801:Humans; D008297:Male; D010375:Pedigree; D013255:Steroid 21-Hydroxylase / Q000235:genetics
chemical_list: D003181:Complement C4; D006680:HLA Antigens; D015934:Complement C4a; D015935:Complement C4b; D004247:DNA; D013255:Steroid 21-Hydroxylase; D004262:DNA Restriction Enzymes