This report presents the methodology and findings of a project whose objectives were to identify SNPs in the literature that could provide information on ancestry and pigmentation; obtain samples from volunteers that collected data on ancestry and pigmentation; type the selected SNPs; select a sub-panel of SNPs providing the maximum amount of information; and develop an assay that can be used to type forensic samples.
These objectives are important, because an STR DNA profile obtained from crime scene evidence often does not match identified suspects or profiles from available databases. In such cases, further DNA analyses targeted at inferring the possible ancestral origin and phenotypic characteristics of the perpetrator (hair color, skin color, and eye color) could provide useful information on suspect characteristics. Using models with recommended thresholds, the 50 SNP assay provided accurate ancestry information in 98.6 percent of the test set samples and also provided accurate eye color information in 61 percent of the European samples tested (25 percent were determined inconclusive, and 14 percent were incorrect). The assay, which uses equipment already available in forensic DNA laboratories, is recommended for use in forensic casework to provide additional information about the donor of a DNA sample when the STR profile has not been linked to a known individual. The project used single base primer extension (SBE) technology to develop a 50 SNP assay designed to predict ancestry among the primary U.S. population (African American, East Asian, European, and Hispanic/Native American), as well as pigmentation phenotype among Europeans. This assay was optimized to a sensitivity level comparable to current forensic DNA analyses and showed robust performance on forensic-type samples. 43 figures and 13 tables
Report (Grant Sponsored)
Date Published: October 1, 2014