DNA "manhunt" by searching the Y-STR Haplotype Database.

Korean J Leg Med. 2005 May;29(1):87-93. Korean.

Department of Forensic Medicine, Central District Office, National Institute of Scientific Investigation, Korea. cns6999@nisi.go.kr

We report here the application of Y-chromosomal DNA analysis and haplotype Database search in a rape case, which occurred in Daejeon city (central region of Korea). At March 2004, a woman was sexually assaulted in her house by an unknown offender. Information of the offender was insufficient. DNA was extracted from vaginal fluid of victim and analyzed with the PowerPlex Y system (Promega, USA) and the multiplex AmpFl STR Profiler (Applied Biosystems, Foster City, USA). After 8 months, a buccal swab of the suspect unrelated with this case was sent to our laboratory by police. We analyzed DNA using the same method and used this haplotype to search in the Y-STR Database generated by our DNA laboratory. We found only one match in the Korean population sample of 659 Y-STR haplotypes. The suspect and the actual criminal showed an identical Y-STRs haplotype in all Y-chromosome STR loci analyzed and possessed common alleles in 8 out of 9 autosomal loci. We suggested that the actual criminal could be a man closely related to the suspect. After few days, this information was sent to the police and the DNA sample of actual criminal was obtained. Result of analyzed DNA profile revealed that his profile exactly matched all 21 autosomal and Y-chromosome STRs analyzed in the rape case, which occurred in Daejeon city. The frequency of the DNA profile identified was estimated to be 1.67x10-11. The actual criminal was arrested and confessed his crime. Our experience shows that Y-STR Database search is very useful method to detect a real rapist when the database is usually equipped with software facilitating the comparison of all Ychromosome STRs haplotypes stored.

Key Words : Y-STR haplotype. Database. Rape case. DNA profile