The development of latent fingerprints has been a tremendous technique of solving criminal cases in the recent years. However, some of the laboratory reagents and chemical treatments that are used to develop the prints can interfere with the collection of DNA. Some of the reagents and chemical treatments that can interfere with the development of DNA include; Sticky-side Powder, Un-do plus Sticky-side Powder, Magnetic powder, MMD (multimetal deposition), and UV light amongst other treatments. Perhaps, choosing to use such chemical treatments will typically interfere with the examination of DNA samples that are under investigation. Besides that, DNA examiners should ensure that sweat residues have enough amount of cellular material for successful DNA analysis. They should also prevent DNA contamination through additional DNA. Despite the fact that most chemical treatments and use of reagents are the most successful criteria for developing DNA, it is advisable to select reagents that cannot interfere with DNA samples for successful examination (Donovan & McCullen, 2012).
The presence of stains of blood with epithelial cells from other sources is one of the hazards of touch DNA contamination when examining scenes for latent prints. Other risks include; absence of possible tests, the presence of profiles that are not sufficient enough to enter into CODIS, and partial profiles that are likely to yield insufficient statistics. Besides, complex mixtures of DNA samples like the presence of both background and crime-related DNA is also considered as a hazard of touch DNA contamination. Late touch to DNA request for the purpose of examining shared evidence, traces of background DNA that may be obtained from an item of clothing that was initially handled by the manufacturer or other people, and re-examination of cold cases where DNA sensitivity was not considered in the first place are also hazards of touch DNA contamination. Touch DNA will never tell the examiner “how” or “when” a DNA sample was deposited. Since touch DNA has developed to be the most successful and frequently requested DNA test technique, qualified examiners should ensure that they are aware of the possible limitations and avoid them whatsoever for continued reliability and efficiency of their laboratory results (Butler, 2012).
- Butler, J. M. (2012). Advanced topics in forensic DNA typing: Methodology. Walthan, MA: Elsevier/Academic Press.
- Donovan, E. J., & McCullen, R. G. (2012). DNA testing and data banking. Hauppauge, NY: Nova Science.