Short tandem repeat analysis in Japanese population

Short tandem repeats (STRs), known as microsatellites, are one of the most informative genetic markers for characterizing biological materials. Becaus e of the relatively small size of STR alleles (generally 100-350 nucleotide s), amplification by polymerase chain reaction (PCR) is relatively easy, af fording a high sensitivity of detection. In addition, STR loci can be ampli fied simultaneously in a multiplex PCR. Thus, substantial information can b e obtained in a single analysis with the benefits of using less template DN A, reducing labor, and reducing the contamination. We investigated 14 STR l oci in a Japanese population living in Sendai by three multiplex PCR kits, GenePrint(TM) PowerPlex(TM) 1.1 and 2.2. Fluorescent STR System (Promega, M adison, WI, USA) and AmpF/STR Profiler(TM) (Perkin-Elmer, Norwalk, CT, USA) . Genomic DNA was extracted using sodium dodecyl sulfate (SDS) proteinase K or Chelex 100 treatment followed by the phenol/chloroform extraction. PCR was performed according to the manufacturer's protocols. Electrophoresis wa s carried out on an ABI 377 sequencer and the alleles were determined by Ge neScan(TM) 2.0.2 software (Perkin-Elmer). In 14 STRs loci, statistical para meters indicated a relatively high rate, and no significant deviation from Hardy-Weinberg equilibrium was detected. We apply this STR system to patern ity testing and forensic casework, e.g., personal identification in rape ca ses. This system is an effective tool in the forensic sciences to obtain in formation on individual identification.