The Effects of Fingermark Enhancement Light Sources on Subsequent PCR-STR DNA Analysis of Fresh Bloodstains

Abstract

This paper describes a study designed to investigate the effects of light sources used to enhance fingermarks on the subsequent polymerase chain reaction (PCR)-short tandem repeat (STR) analysis of bloodstains. Dried bloodstains on glass were exposed for up to 30 min to five different light sources: Argon ion laser, Polilight UV, Polilight green, Superlite, and shortwave UV. The bloodstains were subsequently analyzed using a quadruplex PCR system. It was found that treating the bloodstains with four of the five light sources had no appreciable effect on the results obtained from subsequent PCR analysis. However, exposure of the bloodstains to shortwave UV light for more than 30 s precluded the acquisition of results from PCR testing. Therefore, under casework conditions, it would be preferable to avoid exposing bloodstains, on which PCR typing is to be performed, to shortwave UV.

DNA typing of fingerprints using capillary electrophoresis: Effect of dactyloscopic powders

“…A study was already performed that demonstrated that DNA typing of biological stains such as blood and saliva was not affected by the use of cyanoacrylate, gentian violet, ninhydrin or amorphous carbon [10]. Other investigations studied the influence of different (laser) lights and fingerprint enhancement light sources on DNA typing of human bloodstains [11,12]. This present study investigates the use of a variety of dactyloscopic powders before DNA typing with the STR methodology, and will differentiate between the different dactyloscopic powders used.…”

Forensic DNA Analysis

“…In general, these development techniques have been shown to not harm polymerase chain reaction (PCR) based DNA testing, but as shown in Table 63.1 there are some exceptions. For example, prolonged exposure (>30 seconds) to a shortwave UV light source has been shown to harm DNA (Andersen and Bramble 1997), and if 63 Forensic DNA Analysis Physical methods Black/white powder No interference, but caution: powder will inhibit PCR and must be removed during extraction Stein et al 1996;van Oorschot et al 2003 Flame soot No interference Grubwieser et al 2003 Manoxol-molybdenum No interference Grubwieser et al 2003 Physicochemical methods Iodine and chemical fixing No interference Grubwieser et al 2003 Cyanoacrylate fuming and cyan colouring…”

Feasibility of a handheld near infrared device for the qualitative analysis of bloodstains

“…Another disadvantage of this technique is that certain types of radiation (i.e. ultra-violet) may cause damage to DNA present within the sample [5,6].…”

“…A number of studies have already been performed to determine the effectiveness of various spectroscopic techniques for the identification of biological fluids, including ultravioletvisible (UV-vis) [21], infrared (IR) [23][24][25] and Raman spectroscopy [26][27][28][29]. While UV radiation may damage DNA contained within a fluid sample [5,6], IR spectroscopy has proven to be an interesting means to 'fingerprint' body fluids as this technique can determine the presence of specific classes of molecules in body fluids with sample volumes as small as 10 -20 μL [23][24][25]. Nevertheless, most of the IR studies carried out so far employ benchtop instruments that cannot be taken to the crime scene.…”