Population study of the Combined DNA Index System (CODIS) core loci D3S1358, D5S818, D8S1179 short tandem repeat (STR) polymorphisms in Sri Lanka

Short tandem repeats (STRs) are a group of highly polymorphic loci in the human genome. STR loci consist of tandemly repeated sequences of 2-7 base pairs in length. As they are small in size STR loci can easily be amplified by the polymerase chain reaction (PCR). Allele frequencies of short tandem repeat loci D3S1358, D5S818, D8S1179 were analyzed by PCR amplification and polyacrylamide gel electrophoresis in 50 unrelated Sri Lankan individuals. All STR loci were in Hardy-Weinberg equilibrium. Statistical parameters of forensic importance, the power of discrimination (PD), observed heterozygosity value (H), polymorphic information content (PIC), typical paternity index (PI) and power of exclusion (PE) were calculated for the loci. These parameters indicated the usefulness of the loci in paternity testing and individual identification in the Sri Lankan population. The combined power of discrimination was 0.926. This is the first time that Sri Lankan population data for D3S1358, D5S818, and D8S1179 loci of forensic importance are reported.