Date of Award
Spring 5-31-2018
Document Type
Thesis
Degree Name
Master of Science (MS)
Department/Program
Forensic Science
Language
English
First Advisor or Mentor
Mechthild Prinz
Second Reader
Lissette Delgado-Cruzata
Third Advisor
Elayne Schwartz
Abstract
There are hundreds of untested sexual assault kits in police custody. As of 2017, New York State passed a law stating that all untested kits must be turned over to forensic laboratories to be tested, causing backlogs at laboratories to increase. The Y-Screen assay is a DNA extraction protocol which utilizes NaOH to rapidly lyse epithelial and sperm cells, and the Quantifiler Trio DNA quantification kit to detect the presence or absence of male DNA prior to standard sample processing. The Y-Screen assay is a commercial product used in this research to test a defined set of validation samples with or without a male contributor. Here we found that there is a correlation between the results of the Y-Screen assay and the results of the standard extraction and DNA typing. For most samples that tested positive with the Y-Screen assay, male DNA profile results were detected after amplification and electrophoresis of the same sample. If the Y-Screen results were extremely low (below the amplification threshold of .0007ng/μl) then, it is likely that the downstream DNA profile will not yield male DNA either. After implementation of the Y-Screen assay a total of 669 casework swabs were tested and from that number 352 (approximately 53%) swabs tested positive for the presence of male DNA without undergoing serology testing. The types of swabs testing positive were vaginal, vulvar, anal, perianal, and dried secretion swabs. The swabs that usually tested negative were the oral swabs. Of the 26 samples entered into CODIS, 30% (or 8) had hits. In conclusion the Y-Screen assay, effectively streamlines the processing of sexual assault kits (SAK) samples.
Recommended Citation
Luyando, Kassandra, "The Y-Screen Assay: Validation and Evaluation of Subsequent STR Success" (2018). CUNY Academic Works.
https://academicworks.cuny.edu/jj_etds/85
