An assessment of DNA extraction methods from blood-stained soil in forensic science. (December 2022)

• Record Type: Journal Article
• Authors: Howarth, Alexandra; Drummond, Bradley; Wasef, Sally; Matheson, Carney D.
• Is Part Of: Forensic science international. Volume 341(2022)
• Publication Date: 2022-12
• Subjects: DNA extraction -- Blood-stained soil -- Pre-treatment -- Humic acids -- Inhibition -- Degraded DNA -- Forensic soil -- DNA profile; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2022.111502
• Languages: English
• ISSNs: 0379-0738

Abstract

Abstract: In forensic crime scene investigations, biological fluids such as blood are commonly found in soil. However, the analysis of blood-stained soil can be challenging due to the presence of inhibitors which limit the effective extraction and amplification of the deoxyribonucleic acid (DNA) required to produce a reportable DNA profile. There are some extraction methods that have been applied to blood-stained soil in forensic science, but these have produced sporadic results. This research has taken a number of different extraction methods from the fields of ancient DNA and environmental DNA and broken them down into the individual steps of pre-treatment, incubation, separation and purification. These steps were assessed independently then combined into various extraction methods to determine the best technique that can effectively and reliably profile human DNA from blood-stained soil. Testing involved assessment of three extraction buffers, (cetyltrimethylammonium bromide, guanidine thiocyanate, and proteinase K), four pre-treatment methods, (polyvinylpyrrolidone, ethylenediaminetetraacetic acid, hydrochloric acid, and sodium hydroxide), three separation steps, (centrifugation, phenol chloroform, and chloroform) and four purification steps, (size exclusion chromatography, bind elute columns, isopropanol precipitation and silica magnetic beads). The most effective procedure was found to be a polyvinylpyrrolidone pre-treatment with a proteinase K extraction buffer followed by magnetic silica bead purification with or without centrifugation. However, centrifugation separation was found to be equally effective after the pre-treatment step as after the incubation step. Our results shows that most of the current forensic procedures would benefit from the addition of a pre-treatment step prior to processing through the automated DNA profiling pipeline. Highlights: A proteinase K with silica bead purification is best for the extraction and profiling of human DNA from blood-stained soil. A PVP pre-treatment prior to DNA extraction improves the ability to generate a human DNA profile from blood-stained soil. A PVP pre-treatment step can be added to any current proteinase K extraction method currently being used in forensic science.