TUMOR-NECROSIS-FACTOR MICROSATELLITES IN 4 EUROPEAN POPULATIONS

The human genome contains a large number of interspersed simple repeat sequences that vary in length among individuals and can therefore ser ve as highly informative polymorphic markers. Several such variable si tes (microsatellites) have been described within the TNF genes within the MHC. In this study, individuals from four Caucasian populations ha ve been typed for three TNF-associated microsatellites in order to def ine their haplotypes. Of the 208 possible haplotypes, eight exist at a high frequency in all populations and account for approximately 60% o f the haplotypes studied, but with marked variations in their frequenc ies among populations. A few population/sample-specific haplotypes hav e been identified. The ability of alleles to define haplotypes uniquel y varies not only among the loci, but also among the alleles: some all eles displaying complete gametic association (linkage disequilibrium) and others displaying very little.