Major histocompatibility complex (MHC)-linked microsatellite markers in a founder population

The Finnish population is genetically relatively homogeneous and has a narr ow gene pool as a result of founder effect followed by rapid population gro wth. We here demonstrate that microsatellite markers are highly informative tools for major histocompatibility complex (MHC) analysis in this populati on. First, no variation in 12 MHC-linked microsatellites could be observed in certain CYP21-deficient chromosomes, which as a result of founder effect most likely derived from common ancestors. Second, amongst 131 Finnish chr omosomes, some, but not all, apparently HLA-identical chromosomes also carr ied identical microsatellites, suggesting that these loci could be applied for identification of haplotypes which have a relatively recent shared orig ins. Finally, when the microsatellites were studied between ethnically more distant individuals (Finnish vs, non-Finnish), who were matched for the HL A alleles, much more differences were observed. This showed that the simila rity in microsatellites was population specific. The microsatellite typing can therefore be informative in fine mapping MHC-linked susceptibility gene s and can help in matching bone marrow transplants in isolated populations. Linkage disequilibrium was found to be much higher in the MHC than in anot her region (5q31) of similar size, indicating that there may be particular mechanisms keeping the MHC haplotypes conserved.