Evaluation of Commercial Kits for Dual Extraction of DNA and RNA from Human Body Fluids^,,

Abstract

STR typing of DNA evidence can identify the donor with a high power of discrimination but cannot identify the tissue origin of a body-fluid stain. Using RNA to attribute a crime scene stain to a particular tissue may aid in reconstruction efforts. With blood from 10 donors, four DNA and RNA coextraction kits were evaluated by measuring yields and STR and mRNA profiles. T tests indicated some significant differences in kit performance. The Zymo Research ZR-Duet(™) kit performed best based on average DNA (41.4 ng) and mRNA (4.07 ng) yields and was the only kit to provide complete DNA/RNA profiles for all samples. The consistency of this kit was challenged by data from additional blood and saliva donors. Further testing is advised before a superior kit is unequivocally chosen. Stand-alone DNA or RNA purification generally offers higher yield, but coextraction may still allow successful STR profiling and tissue source identification.

Human DNA extraction from whole saliva that was fresh or stored for 3, 6 or 12 months using five different protocols

“…Commercial kits are generally the most commonly used, generally presenting more consistent results. This consistency of DNA extraction from saliva using the QIAamp DNA kit is apparent when comparing the results of this study with other investigations 18 , 20 . The same can be said when comparing this study’s results to other investigations when looking at the results obtained by using the Oragene Genotek kits 20 .…”

“…As in the present study, there are several other studies that aimed to establish which DNA extraction from saliva protocols were the most efficient 1 , 9 , 12 , 18 , 20 . Commercial kits are generally the most commonly used, generally presenting more consistent results.…”

“…Briefly, a group of researchers 18 stored saliva at -20°C for 6 months using the QIAamp DNA kit for DNA extraction. When comparing the concentration and quality of DNA extracted from this saliva to the present study, at the same storage durations, the results are in close agreement.…”

Automation of DNA and miRNA co‐extraction for miRNA‐based identification of human body fluids and tissues

“…The identification of biological stains and tissues can provide crucial insight into crime scene reconstruction and connect a suspect to a crime scene . Because of that, not only the attribution of a crime scene related trace to a certain perpetrator, but also the character of the trace itself (e.g.…”

Detection of microRNAs in DNA Extractions for Forensic Biological Source Identification

“…MiRNA analysis still requires a separate RNA extraction and therefore consumes valuable sample (). Previous work has proposed or evaluated DNA/RNA coextraction methods for RNA detection using one or more of the typically discarded washes, but a complete evaluation of the most common forensic DNA isolation and purification methods has not been undertaken in a single study (). The previous reports showing miRNA detection from silica column DNA extractions did not address the exact mechanism of coextraction ().…”