Volume 44, Issue 1 (January 1999)
Deoxyribonuclease I Phenotyping from Saliva Stains
Good typing results were obtained using a newly developed method for extraction and purification of deoxyribonuclease I (DNase I) from saliva stains. Previously, DNase I phenotyping from saliva stains has been unsuccessful because of low enzyme activity and heavy contamination. Salivary DNase I was extracted from stains using phosphate buffer containing Nonidet P-40. Extracts were purified using Phenyl Sepharose CL-4B gel. Electrophoresis was performed, and DNase I was successfully phenotyped. All of the DNase I phenotypes, which were obtained from saliva stains using this new method, were identical to the phenotypes determined from urine samples. Moreover, DNase I was correctly phenotyped from saliva stains that had been stored for over three months at room temperature or at 37°C. These results suggest that DNase I polymorphisms provide valuable information for forensic characterization of saliva stains.