Frequency of extragenic polymorphisms in alleles bearing normal prothrombin 20210G (▪) and mutant prothrombin 20210A (□). (A) Five diallelic polymorphisms designated by their rs number (NCBI SNP database). (B) Nine microsatellites (depicted are only the alleles with a frequency of more than 2.5% in either normal or mutant alleles). The number of chromosomes examined, distance of each polymorphism from the mutation, and the statistical significance of the difference in the frequency between the normal and mutant alleles are shown.