Familial DNA searching for identifying missing and unidentified persons in South Africa

Abstract

Familial DNA searching (FDS) exploits partial genetic relatedness within forensic DNA databases to identify missing persons and unidentified human remains (MPUHRs). In South Africa, despite statutory provision for familial searching under the Criminal Law (Forensic Procedures) Amendment Act, operational use within the National Forensic DNA Database of South Africa (NFDD-ZA) remains unrealized. This article presents an overview and critical integrative review of the forensic science literature on familial searching, synthesizingempirical, methodological, and policy-oriented evidence to evaluate implications for forensic practice and governance. Autosomal STR profiling remains the principal foundation of familial searching, with likelihood-ratio-based ranking consistently outperforming allele-counting approaches. Integration of Y-STRs or SNPs improves discrimination in complex kinship scenarios. Effective implementation across jurisdictions depends on pre-validated likelihood-ratio decision thresholds (τ), defined through empirical validation studies to control false-positive rates. FDS can be implemented in South Africa in a scientifically robust and ethically defensible manner through staged deployment, formal governance frameworks, and independent oversight, with particular value for MPUHR identification.