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Development of a High-Throughput Method to Isolate Sperm DNA in Sexual Assault Cases

NCJ Number
Date Published
31 pages
This study evaluated and optimized the track-etch filtration method for isolating sperm for DNA analysis and compared this method to the standard differential extraction protocol using multiple amplification kits and sequencer platforms.
Results indicated that the ISOPORE track-etch filter was effective at identifying the DNA profile of a semen donor from a sample of mixed body fluids. The track-etch filter separation technique was equal or superior to the standard differential extraction method for identifying DNA profiles, but the track-etch filter method took much less time than the standard differential extraction method, saving over 2 hours. The track-etch filter method was improved by minimizing the problem of filter clogging through RNase treatment. However, it will be necessary to remove epithelial cell debris without a pelleting step in order to fully automate the method. Automation is desirable to reduce the thousands of backlogged sexual assault cases waiting to be processed. Semen was collected from healthy male volunteers and an average number of sperm per microliter was determined through the use of a hemocytometer. Buccal swabs were collected from healthy female donors and approximately 100,000 sperm were added to the swabs and were then extracted using both the track-etch filtration method with and without RNase treatment and the standard differential extraction method. Additionally, 10 sexual assault evidentiary samples from 9 previously adjudicated cases were processed using both the track-etch filtration method and the standard differential extraction method. Simple fixes needed on the track-etch filtration method included filter leakage and popping. Tables, figures, references
Date Published: January 1, 2006