Characterisation of identity-informative genetic markers in the Australian population with European ancestry

Identity-informative single nucleotide polymorphisms (iiSNPs) are valuable genetic markers for human identification and kinship testing in forensic casework, especially when the quality and quantity of DNA evidence is not suitable for routine short tandem repeat (STR) profiling. This study analysed 105 buccal samples representing the Australian population with European ancestry in order to assign allele frequencies and conduct population genetic analyses for 94 iiSNPs and 20 STRs. The markers were assessed by calculating relevant forensic statistics and testing for deviations from Hardy-Weinberg and linkage equilibrium. No linkage of statistical significance was observed between any of the pair-wise combinations of the combined 114 identity-informative markers and only one STR exhibited deviation from Hardy-Weinberg equilibrium (D8S1179). The probability of matching genotypes being observed within this population was of the order of 10⁻²³ for STRs, 10⁻³⁸ for iiSNPs and 10⁻⁶⁰ for the combined identity-informative marker panel, improving the ability to discriminate between individuals when calculating likelihood ratios in direct or indirect matching scenarios. Further, the addition of iiSNPs will facilitate identifications when suboptimal STR profiles are recovered from compromised or challenging samples and aid comparisons to genetic relatives for familial or kinship testing.