Three short tandem repeat loci in Japanese population

Area of Science:

• Forensic Science
• Genetics
• Molecular Biology

Background:

• Short tandem repeats (STRs) are crucial genetic markers for human identification.
• Assessing the polymorphism of specific STR loci in diverse populations is essential for forensic applications.
• Previous studies have highlighted the utility of STR analysis in various identification scenarios.

Purpose of the Study:

• To determine the allele frequencies and polymorphism of three STR loci (vWF, TH, and GCG) in a Japanese population.
• To evaluate the combined discrimination power of these STR loci for individual identification.
• To assess the applicability of these STR loci in forensic casework, particularly with degraded samples.

Main Methods:

• Polymerase Chain Reaction (PCR) amplification of vWF, TH, and GCG STR loci.
• Analysis of PCR products using gel electrophoresis to determine allele sizes.
• Calculation of allele frequencies and forensic statistical parameters.
• Application of selected STR loci to a severely decomposed forensic specimen.

Main Results:

• High polymorphism was observed for all three STR loci in the Japanese individuals studied.
• vWF locus showed 8 alleles, TH locus had 7 alleles, and GCG locus exhibited 13 alleles.
• The combined discrimination power of the three STR loci was calculated to be 0.995.
• STR loci vWF and TH provided clear results for the decomposed forensic sample, while GCG typing was unsuccessful due to excessive background noise.

Conclusions:

• The vWF, TH, and GCG STR loci are highly polymorphic and suitable for the identification of Japanese individuals.
• The vWF and TH loci demonstrate utility in forensic identification, even with severely decomposed samples.
• Further optimization may be needed for the GCG locus in challenging forensic cases.