The assessment of the efficacy of STRs panels recommended by the ISAG for canine pedigrees analysis for forensic casework

Canine DNA is widely used in forensic investigations, particularly in cases of dog attacks on humans. Nowadays, STR markers are employed worldwide in forensic laboratories to test human and animal genotypes. In the study we analysed the effectiveness of 18 STR panel as previously recommended by ISAG and the same panel with three additional markers – 21 STR, which has been recommended by ISAG as the core panel for dog identification since 2016. We calculated the PD, P_ID for these sets of panels and estimated RMP based on the DNA profile obtained during an investigation of a woman bitten by a dog. The high combined CPD value for 18 and 21 STRs showed values close to 1.0. The CP_ID value for theses panels was 5.2 × 10⁻¹⁰ to 6.4 × 10⁻¹⁴. Statistical analysis estimated the random DNA match, in the case of the woman bitten by a dog, with a probability of 4.3×10¹⁹ and 2.8×10²², using 18 and 21 STR panels respectively, and that the canine DNA profile from the crime scene originated from the suspected dog and not from another random dog. Our results show that both STR panels can be used effectively for individual identification and forensic casework.