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Exploring the DNA mixture deconvolution through simulation

NCJ Number
Australian Journal of Forensic Sciences Volume: 51 Pages: S14-S17
Date Published
4 pages

This article introduces a simulation method to explore the range of likelihood ratios that is expected to be obtained when a non-donor or a true donor is compared with the mixed DNA profile.


If an unambiguous single-source DNA profile is obtained from a crime scene, then a potential person of interest can either match or not match the crime scene profile, and the likelihood ratio for the single matching genotype can be easily computed. Mixed DNA profiles, on the other hand, are typically ambiguous; and a vast number of different likelihood ratios can be obtained, depending on the genotype of a potential person of interest that is compared with the mixture later. In the absence of a person of interest, it can be unclear how suitable the profile is for discriminating between donors and non-donors. In the simulation method presented in the current article, sampling is conditional on the mixture deconvolution obtained using probabilistic genotyping. These simulations help to decide whether a (mixed) profile is suitable for comparison to a person of interest. Moreover, the methods can be used to determine whether a profile is suitable for upload to a database and whether potential rework could be advised. (publisher abstract modified)

Date Published: January 1, 2019