Comparison of Likelihood Ratios from Probabilistic Genotyping for Two-Person Mixtures across Different Assays and Instruments

Continuous probabilistic genotyping (PG) provides a means to estimate the probative value of DNA mixtures tendered as evidence in court and subject to alternative propositions about the contributors to the mixtures. The weight of that evidence, however, may be valued differently, depending on which...

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Bibliographic Details
Published inForensic sciences (Basel, Switzerland) Vol. 4; no. 3; pp. 441 - 452
Main Authors McNevin, Dennis, Barash, Mark
Format Journal Article
LanguageEnglish
Published MDPI AG 02.09.2024
Subjects
comparison
DNA mixture
probabilistic genotyping
PROVEDIt
short tandem repeat
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Summary:Continuous probabilistic genotyping (PG) provides a means to estimate the probative value of DNA mixtures tendered as evidence in court and subject to alternative propositions about the contributors to the mixtures. The weight of that evidence, however, may be valued differently, depending on which forensic laboratory undertook the DNA analysis. There is a need, therefore, to have a means for the comparison of likelihood ratios (LRs) generated by continuous PG amongst different laboratories for the same initial DNA sample. Such a comparison would enable the courts and the public to make judgements about the reliability of this type of evidence. There are particular mixtures and methods for which such a comparison is meaningful, and this study explores them for the short tandem repeat (STR) electropherograms of two-person mixtures obtained from the PROVEDIt Database. We demonstrate a common maximum attainable LR for a given set of common STR loci and a given DNA mixture that is consistent across three different STR profiling assays and two different capillary electrophoresis instruments.
ISSN:2673-6756
2673-6756
DOI:10.3390/forensicsci4030028