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The effect of an enzymatic bone processing method on short tandem repeat profiling of challenged bone specimens

NCJ Number
Legal Medicine Volume: 15 Issue: 4 Dated: 2013 Pages: 171-176
Date Published
6 pages

This study assessed two methods, mechanical sanding and enzymatic trypsin, for cleaning bone specimens prior to DNA isolation.


The forensic analysis of DNA from bone can be important in investigating a variety of cases involving violent crimes and mass fatality cases. To remove the potential presence of co-mingled remains and to eliminate contaminants that interfere with forensic DNA analysis, the outer surface of the bone fragment must be cleaned. The current study compared two methods for cleaning bones on the yield of DNA isolated and the quality of DNA analysis of bone. The comparison study found comparable values of DNA yields between the two methods. In addition, to evaluate the capabilities of the cleaning effect of the bone processing methods, the presence of polymerase chain reaction inhibitors in the DNA extracts was monitored using the internal positive control. Similar Ct values of the internal positive control were observed as the DNA extracts of the trypsin method compared with that of the sanding method. The characterization of the effects of the trypsin treatment on the quality of DNA profiling was also conducted. To evaluate the integrity of the nuclear DNA isolated, the percentage of allele calls and the peak-height values of alleles of the short tandem repeat profiles were compared for the two methods. A paired-sample t-test revealed no significant difference between the two methods. Study data indicate that the trypsin method can be used as an alternative cleaning method to mechanical cleaning methods. This method can be used to process multiple samples simultaneously. This is important for achieving high-throughput DNA isolation through potential automation, which can be useful for the forensic DNA analysis of skeletal remains from mass fatality incidents. (publisher abstract modified)

Date Published: January 1, 2013