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30-Jun-2022
Getting full DNA profiles from handguns
Handguns are a hotbed of DNA evidence. Forensic DNA labs can detect tiny DNA amounts left on a handgun. Labs often pool together DNA taken from different areas of the gun, then amplify it all together to get more signal. But pooling swabs blurs distinctions, losing identification information.
Using smart software – first amplifying areas separately, then analyzing the data jointly – gets better results. When TrueAllele does this "joint" statistical Smith robbed at gunpoint analysis, Cybergenetics software extracts more DNA information from the same gun.
In a study we conducted a dozen years ago, by combining the data from four different handgun areas, we essentially recovered the unique profile of the person handling the gun. We announced this innovation back then in conference talks, papers, and posters.
"How much more informative?", asked Cybergenetics scientist Dr. Mark Perlin in his 2010 ANZFSS talk in Sydney, Australia. "We went from no information with human review, to a unique profile with joint analysis that was a trillion times more informative." Dr. Perlin ended, "In conclusion, it is good to use all of the data, and we get more information when we do."
Why does crime lab software fail so often on handgun DNA? Because most handgun evidence has been handled by five or six people, sometimes more. Their DNA is all mixed together in ways most software cannot decipher. Too many people in the mix, and too little DNA in total, making it too hard for simple programs to handle.
Why does Cybergenetics TrueAllele work so well for solving handgun crime? Because TrueAllele has been solving mixtures correctly for over twenty years. The first and the best. Our technology reliably separates mixtures of ten unknown people. A unique capability.
Why does TrueAllele joint analysis succeed? Because we pioneered making good use of variation in DNA data. And handgun mixtures vary on different parts of a gun. TrueAllele exploits this DNA variation to get sharper genotypes for more information.