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Genetic Study Aids DNA Forensics

NCJ Number
Date Published
October 2009
2 pages
This study found that analysis of a sample of DNA left by an unknown suspect at a crime scene can be used to determine the suspect’s skin pigmentation, natural hair color, and natural eye color with sufficient accuracy to aid investigators in developing a description of the suspect.
Using 1,000 ethnically diverse student volunteers, researchers used DNA analysis to predict both the amount of natural pigment in an individual’s hair and eye color with approximately 76 percent accuracy. Skin color, which is more complex, was accurately predicted at approximately 50 percent accuracy. Researchers measured each student’s skin tone by using a skin reflectometer on the lower portion of the upper arm, where people are not likely to tan. Researchers also took hair samples from the students who had not dyed their hair in the past 3 months, and then determined pigment through chemical analysis. Eye color was determined by comparison with an eye chart available from companies that make artificial eyes. The research team then obtained a DNA sample from each student by swabbing the inside of his/her mouth along the cheeks. Information was entered into a database, and the samples were coded by pigmentation number and DNA number so participants’ identities were unknown.
Date Published: October 1, 2009