Dual examinations for identification of urine as being of human origin and for DNA-typing from small stains of human urine.

Concurrent methods for identification of urine as being of human origin, and for DNA-typing from small stains of human urine were examined. A urine stain was extracted with phosphate-buffered saline (PBS), and the extract was filtered using a Centricon-100 device. The filtrate was subjected to electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS) for identification of human urine and a DNA-typing sample was obtained by dialfiltration of the residue using a DNA purification kit. After the purified residue was treated with an AmpflSTR Profiler PCR amplification kit, the DNA-types were analyzed by capillary electrophoresis using a Genetic Analyzer. It was possible to identify a urine stain as being of human origin, and complete DNA profiles could be successfully obtained from a urine stain which had been created by 50 microL of female urine. Serial analyses of urine stains found at a crime scene provide effective information for forensic investigation. This method is recommended for stain identification and for DNA-typing from a urine stain.

Experimental studies on identification of the driver based on STR analysis.

Identification of the driver based on STR analysis at a crime scene or following a traffic accident would be of enormous assistance in criminal investigation. We performed STR analysis on samples obtained from parts of a car; the steering wheel, the gear lever, the handbrake lever, the indicator lever and the door handle, with a view to obtaining DNA profiles of the owner and any another person who had driven the car just before sampling. As a result, it was found that a cotton swab is suitable for sample collection and that STR analysis of samples from a car, especially from the entire steering wheel, makes it possible to identify of the driver. We conclude that this method is very useful for crime scene investigation, even when the person who had touched the parts of a car had driven only briefly with bare hands.

Successful DNA typing of urine stains using a DNA purification kit following dialfiltration.

To evaluate the utility of DNA polymorphism typing of urine stains in forensic investigations, the amplifiable amount of DNA was estimated in 20 urine specimens obtained from 10 male and 10 female volunteers using a DNA purification kit following dialfiltration. DNA obtained from both urine and urine stains was amplified with the AmpflSTR Profiler PCR Amplification Kit, and was analyzed by capillary electrophoresis using the Genetic Analyzer. The amount of male and female urine necessary for obtaining a complete DNA profile was 0.2 mL and 0.08 mL, respectively. When 0.2 mL of male urine were used to create urine stains, complete DNA profiles could be obtained from just some of the stains. However, when only 0.1 mL of female urine was used, complete profiles could be successfully obtained from all of the stains. DNA on bleached cotton remained amplifiable for 3-6 weeks. This method using a DNA purification kit following dialfiltration can be recommended for the genotyping of urine stains.