Operation Invisible Dead: A Blind Study to Compare Molecular Fingerprints of Soil Samples between Crime Scene and Criminal's Shoe

Abstract

Capillary electrophoresis can separate fragments of nucleic acids using single strand conformation polymorphism (SSCP) This method has been increasingly used in microbial ecology to develop fingerprints of the microbial community within soil. SSCP detects mutations in DNA fragments due to changes in the secondary structure of single‐stranded DNA fragments. Molecular fingerprinting can have a wide application in Forensics. It is important to find if a soil fingerprint from a criminal's shoe can be matched to the fingerprint found in the database. This is a blind study comparing the possible use of CESSCP in Forensics. The soil samples are collected from two locations by two people. Each individual acted as a “criminal” by digging the soil, walking over the soil and buried a small object. One shoe was removed at the “crime scene” and the other shoe was worn home. The soil was collected from the shovel and both of the shoes for each individual. All the soil samples were air dried for 48 hours before DNA was extracted. The samples were then run through polymerase chain reaction (PCR) to amplify and fluorescently tag the genes of interest. The samples will be processed in the Genetic Analyzer using the CE‐SSCP. The results can very well show that CE‐SSCP will not produce similar fingerprints for the shoe worn home and the database, thus inapplicable to Forensics.Supported by National Institute of Justice (25‐6228‐0159‐001).