Speaker Victoria Williamson, from Mike Marciano lab at Syracuse University, presenting "DEPArray and forensic science: incorporation into the US standard workflow " at the DEPArray Annual User Meeting held October 25-26, 2016 in Bologna, Italy.
Crime scene investigation requires collection and analysis of biological evidence for DNA genotyping. Blood, sperm, and epithelial evidence left behind by perpetrators can help investigators acquire a genetic profile of the person who committed the crime.
A problem occurs when a single evidence sample consists of biological fluids contributed by two or more persons (e.g. the victim and the perpetrator). Forensic scientists refer to these samples as mixed biological evidence.Current approaches to mixed biological evidence analysis have limitations, due to the fact that they produce mixed genetic profiles which can only be interpreted by statistical assumptions that introduce uncertainty and degrade the forensic value of laboratory findings.
The DEPArray™ system resolves this uncertainty by enabling forensic laboratory scientists to separate blood cells, from epithelial cells, from sperm cells, with 100% precision. Such separation, prior to genetic analysis, allows distinct profiling of multiple individual contributors by routine DNA identification methods.
DEPArray Forensic Sample Prep Kit
With the ability to analyze even minute mixed biological evidence, the DEPArray system can separate epithelial cells, white blood cells, and sperm cells, and recover 100% pure pools of cells for standard forensic analysis.
The newly developed DEPArray Forensic Sample Prep Kit streamline the sample preparation step before DEPArray sorting with a labor-saving and standardize procedure. The kit includes all the reagents to process the sample from the evidence support material to the DEPArray cartridge and has been specifically designed for the staining of epithelial, sperm and white blood cells before DEPArray sorting.
The workflow below allows the recovery of multiple groups of 100% pure samples for clear-cut genetic profiling.
Compatible with Existing STR Kits
Cells selected, isolated, and collected by the DEPArray system are compatible with DNA-based human identification kits, instrumentation, and software from a variety of suppliers.
When a sample is composed of a single cell type (such as epithelial cells, or sperm cells), but the contribution of multiple individuals is suspected, the ability of the DEPArray™ system to single out and collect single cells for analysis may enable confident DNA-based identification, based on unambiguous STR profiles, of more than one individual.