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DNA Testing 101: Sexual Assault Kits

NCJ Number
252599
Date Published
November 2017
Length
1 page
Annotation
This training resource for grantees of the federal Sexual Assault Kit Initiative (SAKI) provides basic instruction on the screening, testing, workflow, and reporting of testing results for a sexual assault kit (SAK).
Abstract
Information on SAK screening focuses on the features of biological fluid screening and male DNA screening. Information on testing SAK evidence addresses STR testing and Y-STR testing. STR testing is a commonly used nuclear forensic DNA test that targets areas in the DNA that are short, tandem, and repeated. It is the difference in the number of repeats at each location that differ among individuals. This information is compiled to develop a DNA profile. Y-STR testing targets STR regions only on the Y-chromosome found in males. This test produces a Y-STR profile, which can be useful in cases with high levels of female DNA, male-to-male mixtures, and when a known male sample is available for comparison. Workflow consists of descriptions of six steps crime analysts complete in testing biological evidence from a victim's SAK. The section on reporting SAK testing results defines the following eight testing results: 1) No further testing, 2) No results, 3) Partial profile. 4) Full profile, 5) Mixture profile, 6) CODIS eligible, 7) Offender Hit, and 8) Forensic Hit.