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Article
Identification of spermatozoa by tissue-specific differential DNA methylation using bisulfite modification and pyrosequencing
Electrophoresis
  • Kuppareddi Balamurugan, The University of Southern Mississippi
  • Robin Bombardi, The University of Southern Mississippi
  • George Duncan, Broward County Sheriff's Office Crime Laboratory
  • Bruce McCord, Florida International University
Document Type
Article
Publication Date
5-1-2014
Keywords
  • DNA,
  • Forensics,
  • Methylation,
  • Pyrosequencing,
  • Semen identification
Abstract

The focus of this study is to evaluate the application of epigenetic markers as a forensic tool for the determination of semen present in sexual assault cases. A series of genetic loci were screened in order to identify certain epigenetic markers displaying differential methylation that can allow semen to be differentiated from blood, buccal cells, skin epidermis, and vaginal epithelial cells. Of the different loci tested, a panel of six markers, DACT1, USP49, DDX4, Hs_INSL6_03, Hs_ZC3H12D_05, and B_SPTB_03 were identified to contain tissue-specific differential methylation. Samples ranging from 9–21 for each tissue type were collected and subjected to bisulfite modification. The bisulfite modified DNA was amplified by PCR, and analyzed by pyrosequencing to quantitate the level of methylation at each marker. All six markers successfully differentiated semen samples from the other four tissue types analyzed. Sperm DNA was hypomethylated in all but one marker, B_SPTB_03, where this marker showed hypermethylation. Mean methylation percentages for semen samples were statistically significant from mean methylation percentages of the other four tissues studied (p < 0.01). The results of this study demonstrate the applicability of epigenetic markers as a novel tool for determination of spermatozoa and to identify the tissue source of origin of a DNA sample.

DOI
10.1002/elps.201400175
Citation Information
Kuppareddi Balamurugan, Robin Bombardi, George Duncan and Bruce McCord. "Identification of spermatozoa by tissue-specific differential DNA methylation using bisulfite modification and pyrosequencing" Electrophoresis Vol. 35 (2014) p. 3079 - 3086 ISSN: 0173-0835
Available at: http://works.bepress.com/george-duncan/8/