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Abstract:
Luminol has been widely used in the field of crime scene investigations to detect latent blood; however, luminol has the tendency to destroy DNA evidence. Fluorescein, an alternative to luminol for detecting latent blood at a crime scene, does not destroy DNA evidence. This paper demonstrates the successful recovery of DNA from a blood sample treated with fluorescein. DNA was extracted from blood-containing denim substrates after fluorescein was applied to the substrates. The DNA locus, D18S51, was amplified using standard polymerase chain reaction (PCR) techniques, analyzed by electrophoresis, and used to demonstrate that DNA was successfully recovered from the samples.
Introduction
Violent crimes often go unsolved because of the lack of evidence leading to a perpetrator. Therefore, any evidence found at the crime scene is vital to solving the crime. Violent crimes often leave latent evidence, such as DNA, at the crime scene. In the United States, 13 Short Tandem Repeats (STR) loci on DNA strands are employed by the FBI for typing all felons in the National DNA Databank (CODIS) and for analyzing biospecimens found at crime scenes. The 13 core STR loci are CSF1PO, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, FGA, THO1, TPOX, and VWA [1]. According to the literature, it is possible to recover DNA, "typeable at all 13 core CODIS STR loci" [2].
Luminol has been widely used in the field of crime scene investigations to detect latent blood. However, conflicting studies have shown that luminol, when applied to a latent blood sample, loses valuable DMA information [2, 3], likely because of the repeated applications needed to maintain visualization. This is a major drawback to using luminol because any trace blood discovered through the use of luminol could be useless for DNA recovery.
Unlike luminol, fluorescein, a new alternative method for latent blood detection [4], has not been tested for its impacts on DNA recovery. The goal of this study was to determine whether DNA could be recovered from latent blood samples that have been treated with fluorescein. The approach used in this study was to treat denim substrates with blood, use fluorescein on the denim to identify the blood, and extract the blood from the denim using Chelex 100 Resin. After the blood was extracted,...