Abstract: Objective To optimize low copy number（LCN） DNA analysis methods for forensic STR genotyping. Methods Two groups of DNA sample, extracted using either Magnetic bead method or Chelex-100 methods, were previously amplified with a Identifiler PCR Amplification kit, but no genotype was detected. The DNA samples were concentrated using either a drying method or the Microcon-100 method, then amplified using an miniFiler^TM PCR Amplification kit and genotyped. Results Among the 127 DNA samples, 47 samples, previously extracted using the Magnetic bead method, were genotyped with 36% success rate. Eighty samples, previously extracted using the Chelex-100 method, were genotyped with 30% success rate. Conclusion The application of sample concentration methods and miniFilerTM kit can improve the success rate of LCN STR analysis.

Key words: forensic genetics, low copy number, DNA examination