title: Evaluation of a blood-specific DNA methylated region and trial for allele-specific blood identification from mixed body fluid DNA.
abstract: The identification of blood samples obtained from crime scenes has been an important step in forensic investigation. Recently, a novel approach using the blood-specific methylated CpG site cg06379435 has been reported. In this study, we developed a real-time polymerase-chain-reaction-based method that can simply and rapidly quantitate the methylation ratio of cg06379435 and its neighboring CpGs and set the threshold ratios for blood identification by analyzing various body fluid samples. Blood identification using the thresholds was successfully performed in the analysis of a small amount (1ng) of DNA from blood and various aged blood samples, including 29-year-old stains. We also demonstrated a test for allele-specific blood identification from a mixed DNA sample by bisulfite sequencing analysis of these CpG sites and their neighboring single nucleotide polymorphism, rs7359943 (A/G), which is of relevance in cases where mixed samples are obtained from crime scenes. The stability of DNA methylation in aged samples and the usefulness of neighboring genetic information shown in this study suggest that DNA-methylation-based body fluid identification will play a major role in future forensic investigations.
authors: National Research Institute of Police Science, Chiba 277-0882, Japan. Electronic address: k-watanabe@nrips.go.jp.
authors: Ken
authors: K
authors: Watanabe
authors: National Research Institute of Police Science, Chiba 277-0882, Japan.
authors: Tomoko
authors: T
authors: Akutsu
authors: National Research Institute of Police Science, Chiba 277-0882, Japan.
authors: Ayari
authors: A
authors: Takamura
authors: National Research Institute of Police Science, Chiba 277-0882, Japan; Department of Forensic Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan.
authors: Koichi
authors: K
authors: Sakurada
mesh_terms: D000483:Alleles; D001826:Body Fluids / Q000737:chemistry*; D019175:DNA Methylation / Q000235:genetics*; D053803:Forensic Genetics / Q000379:methods*; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
keywords: Bisulfite sequence; Blood identification; DNA methylation; Real-time polymerase chain reaction; Single nucleotide polymorphism