Blood, saliva, and semen are some of the forensically most relevant biological stains commonly found at crime scenes, which can often be of small size or challenging due to advanced decay. In this context, it is of great importance to possess reliable knowledge about the effects of degradation under different environmental conditions and to use appropriate methods for retrieving maximal information from limited sample amount. In the last decade, RNA analysis has been demonstrated to be a reliable approach identifying the cell or tissue type of an evidentiary body fluid trace. Hence, messenger RNA (mRNA) profiling is going to be implemented into forensic casework to supplement the routinely performed short tandem repeat (STR) analysis, and therefore, the ability to co-isolate RNA and DNA from the same sample is a prerequisite. The objective of this work was to monitor and compare the degradation process of both nucleic acids for human blood, saliva, and semen stains at three different concentrations, exposed to dry and humid conditions during a 17-month time period. This study also addressed the question whether there are relevant differences in the efficiency of automated, magnetic bead-based single DNA or RNA extraction methods compared to a manually performed co-extraction method using silica columns. Our data show that mRNA, especially from blood and semen, can be recovered over the entire time period surveyed without compromising the success of DNA profiling; mRNA analysis indicates to be a robust and reliable technique to identify the biological source of aged stain material. The co-extraction method appears to provide mRNA and DNA of sufficient quantity and quality for all different forensic investigation procedures. Humidity and accompanied mold formation are detrimental to both nucleic acids.
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This work was financially supported from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 285487 (EUROFORGEN-NoE). We would like to thank our volunteers for donating the biological samples for this study and Ana Freire Aradas for helpful discussions.
Bauer M, Polzin S, Patzelt D (2003) Quantification of RNA degradation by semi-quantitative duplex and competitive RT-PCR: a possible indicator of the age of bloodstains? Forensic Sci Int 138:94–103CrossRefPubMedGoogle Scholar
Zubakov D, Hanekamp E, Kokshoorn M et al (2008) Stable RNA markers for identification of blood and saliva stains revealed from whole genome expression analysis of time-wise degraded samples. Int J Legal Med 122:135–142. doi:10.1007/s00414-007-0182-6CrossRefPubMedGoogle Scholar
Levings PP, Bungert J (2002) The human beta-globin locus control region. Eur J Biochem FEBS 269:1589–1599CrossRefGoogle Scholar
Chu ZL, Wickrema A, Krantz SB, Winkelmann JC (1994) Erythroid-specific processing of human beta spectrin I pre-mRNA. Blood 84:1992–1999PubMedGoogle Scholar
Sabatini LM, Ota T, Azen EA (1993) Nucleotide sequence analysis of the human salivary protein genes HIS1 and HIS2, and evolution of the STATH/HIS gene family. Mol Biol Evol 10:497–511PubMedGoogle Scholar
Sabatini LM, Azen EA (1989) Histatins, a family of salivary histidine-rich proteins, are encoded by at least two loci (HIS1 and HIS2). Biochem Biophys Res Commun 160:495–502CrossRefPubMedGoogle Scholar