Research article An efficient novel method for analyzing STR loci from a single sperm captured by laser microdissection

The identification of individuals using short tandem repeat (STR) analysis is important in forensic investigation. STR analysis is especially difficult using DNA from a single nucleus. In this study, DNA from a single sperm from a semen smear stained with hematoxylin and eosin (H&E) was captured using a laser microdissection method and amplified using the improved primer extension preamplification (I-PEP) polymerase chain reaction (PCR) method. Amplified DNA was used for STR analysis with the original and 3% primer methods. DNA from 15 STR loci and the amelogenin locus was amplified using an AmpFlSTR 1 PCR Amplification kit (Applied Biosystems). Using the original primer method, it was impossible to genotype the 15 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA). While using less primer (3% dilution), the 15 STR loci and amelogenin locus were determined perfectly in all ofthepreservedsinglesperms.Therefore, thereducedprimermethod ismoreefficientforanalyzingSTRlocifrom asinglespermcapturedbylaser microdissection.