Salivary deoxyribonuclease I polymorphism separated by polyacrylamide gel-isoelectric focusing and detected by the dried agarose film overlay method.

Isoelectric focusing of whole saliva samples on polyacrylamide gels (pH 3.5-5), followed by dried agarose film overlay detection, was employed to determine the type of salivary deoxyribonuclease I (DNase I). Since this detection method had not only a high sensitivity, but also a high band resolution, it was possible to determine DNase I types from saliva samples of 2-5 microL. Pretreatment of saliva samples with neuraminidase simplified the isozyme pattern and enhanced the sensitivity. The DNase I types in all 30 saliva samples showed a good correlation with the types found in the corresponding blood, semen, and urine samples. This preliminary trial indicates that DNase I typing from saliva samples is a new and promising method for individualization of casework samples in the field of forensic biology.