Discrimination power of Investigator DIPplex loci in Finnish and Somali populations

In this study, the suitability of the Investigator DIPplex insertion/deletion polymorphism (indel) kit for forensic casework was assessed through the genotyping of 151 Finns and 175 Somalis. Allele frequency and heterozygosity (H) of this 30-indel marker set were determined, and forensic efficacy was evaluated through estimation of discrimination power (DP), match probability (MP), typical paternity index (TPI), power of paternity exclusion (PE), and polymorphic information content (PIC). A high level of discrimination power was observed for the marker set in both sample groups (CDP > 0.9999). East-west population substructure found previously in uniparental markers within Finland was not evident for this autosomal set (E-W FST = 0.003). High exclusion probability and low subdivision together demonstrate that these markers are well-suited for identification of individuals in Finland. However, values for typical paternity index and power of paternity exclusion were low (TPI range Finns = 0.750–1.190, PE = 0.996; TPI Somalis = 0.680–1.090, PE = 0.986) in comparison to standard STR sets, and thus indels are not recommended for use in paternity or kinship investigations, except as a supplement to other more powerful tools.