title: Development of a Real-Time PCR-Based Method for Analyzing Semen-Specific Unmethylated DNA Regions and Methylation Status in Aged Body Fluid Stains.
abstract: The detection of semen in forensic investigation is considered important evidence of sexual assault. In this study, we report the development of a real-time polymerase chain reaction-based method for identifying semen that can simply and rapidly analyze the semen-specific unmethylated region of the DACT1 gene. Using two fluorescent probes designed for the methylated or unmethylated status, this method could perform quantitative analysis of the methylation status in this region. Furthermore, this method was used to analyze various body fluid samples, including 29-year-old semen and blood stains. The results showed that this method can detect almost exclusively semen or nonsemen signals even in highly decomposed samples, while a few semen or nonsemen samples showed slight signals of the other fluorescence probe. Although there is still a need for further analysis such as setting thresholds to analyze unknown samples, this method could be a useful supplementary tool for identifying semen, especially in old stains such as those in cold-case investigations.
authors: National Research Institute of Police Science, Kashiwa, Chiba, 277-0822, Japan.
authors: Ken
authors: K
authors: Watanabe
authors: National Research Institute of Police Science, Kashiwa, Chiba, 277-0822, Japan.
authors: Tomoko
authors: T
authors: Akutsu
authors: National Research Institute of Police Science, Kashiwa, Chiba, 277-0822, Japan.
authors: Koichi
authors: K
authors: Sakurada
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D001826:Body Fluids; D004396:Coloring Agents; D004247:DNA / Q000032:analysis*; D006801:Humans; D008745:Methylation; D009687:Nuclear Proteins / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012463:Saliva; D012661:Semen / Q000737:chemistry*; D013997:Time Factors
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004396:Coloring Agents; C491683:DACT1 protein, human; D009687:Nuclear Proteins; D004247:DNA
keywords: DNA methylation; aged stain; body fluid identification; forensic science; identification of semen; real-time PCR