Blind Testing and Evaluation of a Comprehensive DNA ...Prediction Results Methods Introduction Blind...
Transcript of Blind Testing and Evaluation of a Comprehensive DNA ...Prediction Results Methods Introduction Blind...
Prediction Results
Methods
Introduction
Blind Testing and Evaluation of a Comprehensive DNA Phenotyping System
Rachel Wiley1, Xiangpei Zeng1, Bobby Larue1, Ellen M. Greytak2, Steven Armentrout2, Bruce Budowle1,3
1) Institute of Applied Genetics, Department of Molecular and Medical Genetics, University of North Texas Health Science Center (UNTHSC), Forth Worth, TX;
2) Parabon NanoLabs, Inc., Reston, VA; 3) Center of Excellence in Genomic Medicine Research (CEGMR), King Abdulaziz University, Jeddah, Saudi Arabia
Predictions Vs. Actual Appearance DNA phenotyping refers to the prediction of ancestry and/or physical appearance from DNA. In forensics, these predictions have the potential to generate new investigative leads in cases
where DNA does not match a known suspect or a database, and to discover more information about unidentified remains. In this study,
the Parabon® Snapshot™ DNA Phenotyping System, which predicts detailed biogeographic ancestry, pigmentation (eye color,
hair color, skin color, and freckling), and face morphology, was evaluated in a blind experiment. This study represents the first public blind evaluation of a comprehensive DNA phenotyping
system, including side-by-side comparisons of the composite images and the actual photographs of each subject.
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This study demonstrated the predictive performance of the Parabon Snapshot DNA Phenotyping system. Overall, the predicted features were consistent with the actual phenotypes:
skin color, eye color, hair color, freckling, and ancestry. This phase of the study serves as a preliminary assessment of Level 1 detail so
that strengths and limitations could be identified to set up a more in-depth analysis of face morphology in phase 2.
Conclusions
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Subject ID – Self-Reported Ancestry
MidEast-W MidEast-N Europe-W Europe-SW Europe-SE Europe-S Europe-NE Europe-N EAsia-SE EAsia-Japan EAsia-Cen CAsia-S CAsia-NE CAsia-N CAsia-E Africa-W
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Predicted Phenotype Consistencies vs. Actual Phenotype 96% 96% 92% Skin Color Eye Color Hair Color
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• 24 subjects recruited for phenotypic and ancestral diversity by the University of North Texas Health Science Center (UNTHSC)
• 25 anonymous DNA samples sent to Parabon, including one
two-person mixture (not made known to Parabon, but Parabon readily detected the mixture and identified the contributors)
• Each sample genotyped on the Illumina CytoSNP-850K chip (851,274 SNPs) and run through the Snapshot algorithms
• Phenotype predictions compiled into a detailed report for each subject, including a predicted composite in which differences from the average face for the same sex and ancestry were
emphasized • Age and body mass index (BMI) values then delivered to
Parabon, and subjects with large differences from default age (25) and BMI (22) age-progressed by a forensic artist
• Photographs and self-reported ancestry and phenotypes collected by UNTHSC, and predictions for each Level 1
phenotype (sex, pigmentation, ancestry) compared to actual phenotypes
• Next phase will incorporate 3D scanning and craniofacial
measurements to assess accuracy of predicted face morphology
Study funded in part by the National Geographic Society
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