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Body Fluid Identification Using Epigenetic Methylation Markers and Pyrosequencing

NCJ Number
Date Published
December 2016
14 pages
Findings and methodology are presented for a project whose goal was to identify and study some of the regions of the human genome called tissue-specific differentially methylated regions (tDMRs), which are known to present methylation patterns typical of specific body fluids.

This is a significant project, because the discrimination of body fluids present at crime scenes can provide valuable information regarding the circumstances linked to the deposition of DNA. Current methods used in forensic laboratories rely on colorimetric detection of enzymes. Due to the unspecific presence of such enzymes in multiple body fluids, current tests are merely presumptive and may also require the use of a large portion of the sample collected. Based on this project's findings, the researchers conclude that the use of epigenetic information on the DNA can be used as a confirmatory test for the determination of body fluid type in forensic laboratories. Enzymes are the product of specific gene expression in certain body tissues and body fluids. Regulatory mechanisms in the human genome are capable of activating or silencing certain genes in specific tissues in order to promote or silence the expression of gene products, such as proteins, depending on whether they are necessary for the biological functions of each specific tissue. Epigenetics is the term used to define such regulatory mechanisms. DNA methylation can present individual patterns in certain loci in the human body that are tissue-specific. The current project identified 10 new genome locations that present patterns specific for semen, saliva, blood, and vaginal epithelia. The results of the current project show the potential of DNA methylation markers as a confirmatory test for body fluid discrimination in forensics. Continued work on identifying new markers and increasing sensitivity is necessary. 4 figures, 1 table, 16 references, and a listing of project publications and presentations

Date Published: December 1, 2016