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                            Library & Multimedia
 Performance of a method for weighting a range in the number of contributors in probabilistic genotyping
NCJ Number
              302743
Journal

*Forensic Science International-Genetics* Volume: 48 Dated: September 2020
Author(s)
          Catherine McGovern;
                        Kevin Cheng;
                        Hannah Kelly;
                        Anne Ciecko;
                        Duncan Taylor;
                        John S. Buckleton;
                        o-Anne Bright
Date Published

September 2020
Annotation
              Taylor et al. have described a method to weigh the probability that the DNA profile under different values of N and incorporate this into a likelihood ratio (LR), and the current paper reports exploration of the performance of this variable number of contributors (varNoC) method programmed within the probabilistic genotyping software STRmixTM.
Abstract
              Uncertainty in the assignment of the number of contributors (NoC) can be encountered, particularly in higher-order mixtures, where alleles may be shared between contributors, may have dropped out, or may be masked by the stutter artefacts or allelic peaks of a more dominant contributor. Most probabilistic genotyping software requires the assignment of NoC prior to interpretation. NoC has been described as a nuisance parameter. In the current project, the desired combination of performance and runtime was obtained using the default STRmixTM version 2.7 MCMC settings in conjunction with a 2.5  percent hyper-rectangle range, at least 10,000 naïve MC iterations and 8 MCMC chains. The varNoC LR demonstrated the typical sensitivity and specificity behavior observed in previous studies, with a high level of reproducibility given repeat analyses. Profiles previously demonstrating ambiguity in the NoC assigned using conventional estimation methods were able to be reliably interpreted and a varNoC LR assigned. (publisher abstract modified)
      
  
          Additional Details
Grant Number(s)
        2017-DN-BX-0136


  
  
        
  Agencies
        NIJ-Sponsored


  
  
        
  Publication Type
        Research (Applied/Empirical)


  
  
        
  Award
        Population Genetic Issues for Forensic DNA Profiles
    
  
  
Date Published: September 1, 2020
    
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