TrueAllele solves uninterpretable DNA in mother and daughter double homicide

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Using TrueAllele® Casework to separate DNA mixtures of relatives

J. Hornyak, W. Allan, and M.W. Perlin, "Using TrueAllele® Casework to separate DNA mixtures of relatives", DNA Workshop, 124th California Association of Criminalistics Seminar, San Francisco, CA, 20-Oct-2014.


PowerPoint presentation with live audio recording of Dr. Perlin's talk.

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In the Fall of 2011, a couple was found inside their home, having died from shotgun blasts. The primary suspect was the couple's son. Four shotgun shells found on the kitchen floor of the crime scene were tested for DNA, with a three-person mixture found on one of the shells.

The lab did not manually review this mixture, since the victims were the suspect's father and mother. To examine a possible DNA connection between the mixture of close relatives, the police and prosecutors asked Cybergenetics to analyze the mixture evidence using TrueAllele® Casework.

TrueAllele Casework is a computer system that uses mathematical modeling to statistically separate the contributor genotypes from a DNA mixture. TrueAllele has been used in hundreds of criminal cases, with reports produced for over 200 cases. DNA experts have testified to TrueAllele results in court over 20 times, and TrueAllele has withstood admissibility challenges in the United States and abroad.

The TrueAllele computer successfully separated the shotgun mixture data into three contributors: major, middle, and minor. The major genotype matched the father with a statistic of about 50 trillion, while the middle one matched the son with a statistic of 5 trillion. The son pleaded guilty to third degree murder, and was sentenced to 25 to 50 years in prison.

This presentation will describe how TrueAllele can be used to separate mixtures of relatives in a criminal case.