TY - JOUR
T1 - Expanded CODIS STR allele frequencies – Evidence for the irrelevance of race-based DNA databases
AU - Oldt, Robert F.
AU - Kanthaswamy, Sreetharan
N1 - Funding Information:
We thank the staff of the Evolutionary and Forensic Genetics Laboratory at Arizona State University, West, and Molecular Anthropology Laboratory at the University of California, Davis, for their assistance with sample preparation. We are also very grateful to two anonymous reviewers whose insightful comments significantly impoved this manuscript. This study was supported by a National Institute of Justice grant 2014-DN-BX-K024 to SK.
Funding Information:
This study was supported by a National Institute of Justice grant 2014-DN-BX-K024 to SK.
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2020/2
Y1 - 2020/2
N2 - The US Federal Bureau of Investigation's (FBI) core Combined DNA Index System (CODIS) short tandem repeat (STR) panel is required for the calculations of random match probabilities (RMPs) in forensic DNA analysis. Current practice dictates that RMPs should be generated across appropriate reference STR allele frequency databases, including African American, Asian, Caucasian, Hispanic, and Native American, when the suspect's race is unknown. Should the suspect declare their race, a specific reference database that pertains to that designation is used. This practice is based on the presumption that racial population group is relevant for calculating conservative RMPs that favor the defendant. The core CODIS panel has been expanded to 20 STRs, however, the relationship between RMP and race has not been re-evaluated. Genetic structure analyses and Bayesian-based population assignment of expanded CODIS profiles from one race-neutral and five race-specific reference databases revealed that STR data could not distinguish races as distinct biological clusters. For instance, while the average race-specific RMPs for Hispanic or Caucasian profiles were almost equally-conservative when calculated from either population's reference database, the Hispanic profiles closely affined with the Native American population. Race-neutral RMPs computed with a correction factor (θ) of 0.03 favor the defendant as much as race-specific RMPs based on a θ of 0.01. Insufficient genetic differentiation observed among the US racial populations as well as inconsequential differences between race-specific and race-neutral RMPs undermine the value of using “race” in the context of forensic DNA analysis and support the argument that forensic databases should be race-neutral.
AB - The US Federal Bureau of Investigation's (FBI) core Combined DNA Index System (CODIS) short tandem repeat (STR) panel is required for the calculations of random match probabilities (RMPs) in forensic DNA analysis. Current practice dictates that RMPs should be generated across appropriate reference STR allele frequency databases, including African American, Asian, Caucasian, Hispanic, and Native American, when the suspect's race is unknown. Should the suspect declare their race, a specific reference database that pertains to that designation is used. This practice is based on the presumption that racial population group is relevant for calculating conservative RMPs that favor the defendant. The core CODIS panel has been expanded to 20 STRs, however, the relationship between RMP and race has not been re-evaluated. Genetic structure analyses and Bayesian-based population assignment of expanded CODIS profiles from one race-neutral and five race-specific reference databases revealed that STR data could not distinguish races as distinct biological clusters. For instance, while the average race-specific RMPs for Hispanic or Caucasian profiles were almost equally-conservative when calculated from either population's reference database, the Hispanic profiles closely affined with the Native American population. Race-neutral RMPs computed with a correction factor (θ) of 0.03 favor the defendant as much as race-specific RMPs based on a θ of 0.01. Insufficient genetic differentiation observed among the US racial populations as well as inconsequential differences between race-specific and race-neutral RMPs undermine the value of using “race” in the context of forensic DNA analysis and support the argument that forensic databases should be race-neutral.
KW - CODIS
KW - Forensic DNA analysis
KW - Population structure
KW - Race
KW - Random match probability
KW - United States
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U2 - 10.1016/j.legalmed.2019.101642
DO - 10.1016/j.legalmed.2019.101642
M3 - Article
C2 - 31786433
AN - SCOPUS:85075556132
SN - 1344-6223
VL - 42
JO - Legal Medicine
JF - Legal Medicine
M1 - 101642
ER -