NCJ Number
245543
Journal
Forensic Science International: Genetics Volume: 9 Dated: March 2014 Pages: 118-133
Date Published
March 2014
Length
16 pages
Annotation
This paper presents a normative approach in deciding between several possible genotype designations for a low-template DNA (lt-DNA) in an attempt to narrow the population of the crime stain's possible donors in submissions to DNA databases for matches.
Abstract
The study found that the IrisPlex is only moderately predictive of eye color in a representative sample of the U.S. population. The difference in the IrisPlex's performance between the European and U.S. populations is explained by the comparatively admixed U.S. population. Based on this finding, the authors advise that additional single nucleotide polymorphisms (SNPs) must be incorporated if the IrisPlex is to be used as a DNA-based eye-color prediction assay. Recently, three additional SNPs associated with the intermediate eye color were discovered and may be informative. The current study evaluated 6 SNPs included in the IrisPlex assay in a population sample (n=200) from a U.S. college campus (Indiana University). The study used a quantitative method of eye-color classification based on (RGB) color components of digital photographs of the eye taken for each volunteer; each eye was placed in one of three color categories: brown, intermediate, or blue. Objective color classification correlated with basic human visual determination, making it a feasible option for use in future prediction assay development. Using these samples and various models, the maximum prediction accuracy of the IrisPlex system after allele frequency adjustment was 58 percent. Detailed descriptions of materials and methods address sample collection, DNA extraction and quantitation, SNP amplification and genotyping, Iris color determination and measurement, and eye-color prediction models. 5 tables, 3 figures, and 27 references