ANALYSIS OF THE MAJOR HISTOCOMPATIBILITY COMPLEX MICROSATELLITE CL1 IN DIFFERENT HUMAN HAPLOTYPES

Characterization of the region between HLA-B and the TNF loci in the h uman MHC revealed the presence of duplicated loci, named CL1 and CL2, that included repeat sequences. Development and use of a PCR typing me thodology that amplified both CL microsatellites simultaneously indica ted that PCR product patterns analysed on native agarose gels were all elic (Abraham et al., 1992). The purpose of the current study was to d etermine the molecular explanation for the unique patterns achieved. S equence analysis of the CL1 locus from 32 chromosomes representing 10 ancestral haplotypes indicated that six alleles were present. The CL m icrosatellites also provided an opportunity to study the evolutionary relationships between MHC haplotypes from different racial groups. Seq uence comparison of closely related ancestral haplotypes from differen t racial groups suggested that the CL1 microsatellite has not changed in the period since divergence.