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Application of Proteinases for DNA Isolation of Bone Specimens

NCJ Number
Richard C. Li Ph.D.
Date Published
34 pages
This report describes two projects that developed a simple sample processing method for DNA isolation from bone specimens and a high-yield DNA isolation method that uses proteinases for bone.
The first project adapted the trypsin bone maceration method for processing bone samples prior to DNA isolation. The results showed that this method was effective for removing soft tissues and the outer surface of bone fragment samples. The short tandem repeat (STR) analysis indicated that no adverse effect on DNA profile was detected after trypsin treatment. The yield of DNA isolated from trypsin-treated bone samples was sufficient for STR analysis; however, the DNA yield of trypsin-treated bone samples was lower than that of untreated bone samples. The data suggest that this trypsin method is an alternative cleaning method to physical cleaning procedures, such as sanding. This method potentially has a low risk of cross-contamination between samples and diminishes safety concerns for laboratory analysts because of exposure to bone powder. This method could be adapted for automated DNA isolation for human identification of bone samples from mass fatality incidents. The second project - which developed a high-yield DNA isolation method using proteinases for bone specimens - tested the hypothesis that the digestion of the matrix protein network in bone structure by the application of proteinases would lead to a degradation of the physical barrier surrounding the osteocytes, thus facilitating DNA extraction. The study found that the clostridiopeptidase A is potent for bone degradation. The application of clostridiopeptidase A can achieve speedy and better bone degradation. The STR analysis showed that no adverse effect on DNA profiles was detected after clostridiopeptidase A treatment. The results indicated that this method improved the DNA yield of bone samples. 10 figures and 18 references