This final National Institute of Justice (NIJ) technical report presents the results of research that examined a proposal for improving methods for studying degraded DNA.
Findings from the research on the proposed method for studying degraded DNA include the following: while sodium hypochlorite was found to be highly efficient (81-99 percent) in removing contaminating DNA from bone surfaces, it did not remove 100 percent of the contamination across all experiments; and sodium hypochlorite was not found to damage endogenous ancient DNA molecules, as previous research has suggested, due to the high variability of mitochondrial DNA (mtDNA) preservation in bone samples. The primary purpose of this study was to validate methods aimed at improving reliability of the analysis of degraded skeletal samples. The research was divided into three phases: 1) determining the efficacy of using sodium hypochlorite in contamination removal from ancient skeletal specimens; 2) evaluation of the overall effectiveness of nine different thermo-stable polymerases and polymerase blends in their ability to amplify mtDNA present in skeletal samples; and 3) evaluating the extent of post-mortem DNA damage in degraded and ancient skeletal samples. Detailed information is presented on the results of each phase of the study. In addition, summaries of two additional studies are included in the report: To Clone or Not to Clone: Method Analysis for Retrieving Consensus Sequences in Ancient DNA Samples; and Cloning May Not Be a Necessary Criterion for the Authentication of Ancient DNA Consensus Sequences and Damage Appears to be Randomly Distributed Across the Human Mitochondrial HVRI Region. Tables, figures, and references
Date Published: January 1, 2012