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Application of Proteinases for DNA Isolation of Challenged Bone Specimens

NCJ Number
Date Published
January 2013
30 pages
Given the need for a less labor-intensive and time-consuming method for cleaning bone specimens prior to DNA isolation, this study compared two methods for processing bone specimens prior to DNA isolation: mechanical sanding and cleaning the bone with enzymatic trypsin.
This study found that cleaning the bone with the trypsin method is a useful alternative to mechanical cleaning methods. Multiple samples can be processed simultaneously, which can expedite the identification of victims of a mass disaster through the DNA analysis of skeletal remains. Comparable values of DNA yields were observed with both mechanical sanding and the trypsin method. In order to assess the integrity of the nuclear DNA isolated, the number of allele calls and the peak-height values of alleles of the short tandem repeat profiles were compared between the two methods. Comparable levels of amplification success of mitochondrial DNA fragments were observed between the two methods. A paired-sample t-test found no significant difference between the two methods. In addition to providing a more efficient method for cleaning bone prior to DNA analysis, the trypsin cleaning method may have a low risk of cross-contamination between samples from airborne bone dust produced by mechanical cleaning. The risk for blood-borne pathogens that may be carried by exposure to bone powder dust is also reduced with the trypsin method. Bone specimens were selected to represent a variety of bone quality and types of bones. A pair of bone fragments was then processed using the sanding and trypsin methods separately for pair-wise comparisons. 7 figures, 4 tables, and 24 references

Date Published: January 1, 2013