New DNA Technique To Help Crime Scene Forensics

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Main Category: Genetics
Article Date: 31 Aug 2008 - 0:00 PDT

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A new article published on August 29th in the open-access journal PLoS Genetics reveals a breakthrough in using DNA to identify possible suspects at a crime scene using DNA. Researchers at the Translational Genomics Research Institute (TGen) are able to use only a small amount of DNA - even if it is mixed with hundreds of other genetic fingerprints - by using genotyping microarrays. The technique allows scientists to identify one person's DNA from a mix of DNA samples despite that individual's representing less than 0.1% of the total mix or the individual being one of 200 individuals.

Not only could the discovery aid police in identifying suspects, but it could also add value in reassessing previous crime scene evidence and could be an asset in other genetic studies and statistical analyses.

Lead author Dr. David W. Craig (Associate Director, TGen's Neurogenomics Division) notes that, "This is a potentially revolutionary advance in the field of forensics" - an interesting diversion from the division's usual charge of investigating ways to treat diseases and conditions of the brain and nervous system. "By employing the powers of genomic technology, it is now possible to know with near certainty that a particular individual was at a particular location, even with only trace amounts of DNA and even if dozens or even hundreds of others were there, too,'' adds Craig.

Historically it has remained a challenge for police investigators to detect an individual if his or her genomic DNA is from a large mix of DNA material or is smaller than 10% of a mix. Researchers have assumed for years that it was impossible to identify individuals using pooled data - an assumption that is now being challenged.

Commander Brent Vermeer (Director, Phoenix Police Department Crime Lab) has said that contamination renders much DNA evidence useless, and it "would be an amazing asset" to eventually put the TGen theoretical research into a cost-effective police practice.

"As technology advances, we need to be prepared to keep evidence that, down the road, could prove again to be useful,'' adds Vermeer.

Resolving Individuals Contributing Trace Amounts of DNA to Highly Complex Mixtures Using High-Density SNP Genotyping Microarrays
Homer N, Szelinger S, Redman M, Duggan D, Tembe W, et al.
PLoS Genetics (2008). 4(8):e1000167.
doi:10.1371/journal.pgen.1000167
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Written by: Peter M Crosta
Copyright: Medical News Today
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