title: Novel identification of biofluids using a multiplex methylation-specific PCR combined with single-base extension system.
abstract: Knowledge of the composition of complex body fluid mixtures may aid forensic investigations greatly. However, many of the traditional tests are presumptive in nature and can lead to ambiguous results. The aim of this study is to establish a reliable method to identify various biofluids via analysis of their DNA methylation profiles.
  
  
  
  A total of eight biofluid-specific methylated markers for saliva, venous blood, vaginal fluids, and semen were isolated from the open database of Infinium HumanMethylation450 BeadChip. These biofluid-specific markers, a control marker to confirm bisulfite conversion, and a gender marker, were combined into a 10-plex methylation-specific PCR single-base-extension (MSP-SBE) system.
  
  
  
  Analysis of 65 DNA samples isolated from venous blood, semen, vaginal fluid, saliva, and menstrual blood that had been treated with bisulfite, resulted in all eight markers detecting the body fluid to which they were designed. Unambiguous body fluid identification occurred from both single sources of body fluids and complex mixtures. A threshold was devised for each marker to minimize the chance of a false inclusion. The efficacy of the assay and application to forensic practice was demonstrated using five non-probative samples from real alleged sexual assault cases. The system unambiguously determined the biofluid types for the non-probative forensic samples that previously resulted in inconclusive or conflicting results using traditional tests.
  
  
  
  The results demonstrated the 10-plex MSP-SBE system established in this study is both sensitive and specific when applied to body fluid identification and can be readily adopted into forensic practice.
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo Kuang Road, South District, Taichung City, 40227, Taiwan, ROC.|Taichung City Government Police Department, 588 Wenxin Road Section 2, Xitun District, Taichung City, 40758, Taiwan, ROC.
authors.forename: Yu-Chih
authors.initials: YC
authors.lastname: Lin
authors.affiliation: Department of Forensic Science, Central Police University, 56 Shu-Jen Road, Kwei-San, Taoyuan, 33304, Taiwan, ROC.
authors.forename: Li-Chin
authors.initials: LC
authors.lastname: Tsai
authors.affiliation: Department of Forensic Medicine, College of Medicine, National Taiwan University, No. 1 Jen-Ai Road Section 1, Taipei, 10051, Taiwan, ROC.
authors.forename: James Chun-I
authors.initials: JC
authors.lastname: Lee
authors.affiliation: Department of Forensic Science, Central Police University, 56 Shu-Jen Road, Kwei-San, Taoyuan, 33304, Taiwan, ROC.|Forensic Biology Division, Criminal Investigation Bureau, National Police Agency, No. 5 Lane 553, Sec. 4, Zhongxiao E. RD., Xinyi District, Taipei, 11072, Taiwan, ROC.
authors.forename: Kuo-Lan
authors.initials: KL
authors.lastname: Liu
authors.affiliation: Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo Kuang Road, South District, Taichung City, 40227, Taiwan, ROC.
authors.forename: Jason Tze-Cheng
authors.initials: JT
authors.lastname: Tzen
authors.affiliation: School of Biological Sciences, Flinders University, Adelaide, 5001, Australia.
authors.forename: Adrian
authors.initials: A
authors.lastname: Linacre
authors.affiliation: Department of Forensic Science, Central Police University, 56 Shu-Jen Road, Kwei-San, Taoyuan, 33304, Taiwan, ROC. mei@mail.cpu.edu.tw.
authors.forename: Hsing-Mei
authors.initials: HM
authors.lastname: Hsieh
mesh_terms: D001774:Blood Chemical Analysis; D002582:Cervix Mucus / Q000737:chemistry*; D019175:DNA Methylation; D005260:Female; D053803:Forensic Genetics; D005819:Genetic Markers; D006801:Humans; D008297:Male; D060885:Multiplex Polymerase Chain Reaction; D012463:Saliva / Q000737:chemistry*; D012661:Semen / Q000737:chemistry*; D013447:Sulfites
chemical_list: D005819:Genetic Markers; D013447:Sulfites; C042345:hydrogen sulfite
keywords: Biofluid identification; Body fluids; DNA methylation; Methylation-specific PCR (MSP); Mixtures; Single-base-extension (SBE)