Polymorphism of the D12S391 microsatellite in a Japanese population sample.

Using the polymerase chain reaction (PCR), we studied the short tandem repeat (STR) polymorphism observed at the D12S391 locus. In 350 Japanese examined, 14 different alleles ranging from 209 bp to 261 bp were detected. Allele 18 (221 bp) showed the highest frequency at 0.30. Observed and expected values of respective genotypes satisfied the Hardy-Weinberg equilibrium (chi 2 = 24.08, P = 0.24, df = 20). In addition, 18 additional sequence structures (suballeles), were detected in this study. Within the suballeles, sequence variants, in which the initial repeat of (AGAT) was replaced with (AGGT), was found in five samples. It was found that the analysis of single-strand conformation polymorphism (SSCP) before sequence analysis was useful for distinguishing these suballeles.