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Forensic Ancestry and Phenotype SNP Analysis and Integration With Established Forensic Markers

NCJ Number
Katherine Butler Gettings
Date Published
August 2013
140 pages
This study used single base primer extension (SBE) technology to develop a 50 SNP (Single Nucleotide Polymorphism) assay designed to predict ancestry and pigmentation phenotype among the primary U.S. populations (African-American, East Asian, European, and Hispanic/Native-American).

The goal of this research was to provide a DNA-based assay and corresponding statistical model that produces ancestry and phenotypic information for individuals whose DNA was collected at a crime scene, but for whom no STR match was found among existing suspects or a DNA database. This goal was achieved. In a forensic case in which a STR profile has not matched any known individuals or database samples, the unknown sample can be genotyped with the 50 SNP assay to provide a predicted likelihood for the unknown individual to be from 1 of the 4 most frequent ancestries in the U.S, population. By entering the 32 genotypes and the U.S. training set into the Web-based application Snipper, a forensic practitioner can quickly generate highly accurate results in a report format. In addition, using a published model and calculator, eye color information can be obtained. In the final phase of the research, a preliminary evaluation of a NGS (next-generation sequencing) method that theoretically is well-suited to forensic samples was performed. The evaluation determined that at this time, the technology is not sufficiently sensitive nor is the read length sufficient to provide a viable alternative to current forensic typing methods. Future project and studies that could stem from this work are outlined. Materials and methods are described in detail. 41 figures, 17 tables, 83 references, and appended supplementary data