Fitting the Balding–Nichols model to forensic databases. (November 2015)

• Record Type: Journal Article
• Authors: Rohlfs, Rori V.; Aguiar, Vitor R.C.; Lohmueller, Kirk E.; Castro, Amanda M.; Ferreira, Alessandro C.S.; Almeida, Vanessa C.O.; Louro, Iuri D.; Nielsen, Rasmus
• Is Part Of: Forensic science international. Volume 19(2015:Nov.)
• Page Start: 86
• Page End: 91
• Publication Date: 2015-11
• Subjects: Balding–Nichols model -- Population genetics -- Partial match probability -- DNA database; Forensic genetics -- Periodicals; Génétique légale -- Périodiques; Forensic genetics; Electronic journals; Periodicals; 614.1
• DOI: 10.1016/j.fsigen.2015.05.005
• Languages: English
• ISSNs: 1872-4973

Abstract

Abstract : Highlights: The Balding–Nichols (BN) model items used to estimate chance allelic matching rates. The typical BN implementation assumes individuals are from the same subpopulation. We must consider individuals from different sub-populations in database analyses. We show how to account for population differentiation in pairwise database studies. Accounting for population differentiation improves the fit to empirical data. Abstract: Large forensic databases provide an opportunity to compare observed empirical rates of genotype matching with those expected under forensic genetic models. A number of researchers have taken advantage of this opportunity to validate some forensic genetic approaches, particularly to ensure that estimated rates of genotype matching between unrelated individuals are indeed slight overestimates of those observed. However, these studies have also revealed systematic error trends in genotype probability estimates. In this analysis, we investigate these error trends and show how they result from inappropriate implementation of the Balding–Nichols model in the context of database-wide matching. Specifically, we show that in addition to accounting for increased allelic matching between individuals with recent shared ancestry, studies must account for relatively decreased allelic matching between individuals with more ancient shared ancestry.