Determining the specificity of the 36-InDelplex panel among species

Insertion-deletion polymorphisms are insertions or deletions of nucleotide bases in the human genome. They have emerged as a promising alternative to Short Tandem Repeats and Single Nucleotide Polymorphisms. This study aimed to evaluate the human specificity of the newly developed 36-InDelplex panel that consists of 34 autosomal InDel loci, the sex marker Amelogenin (AMG-XY), and one InDel locus on the Y chromosome across various animal species.

DNA samples extracted from the leftover blood of 57 animals of a university veterinary hospital that were originally collected for diagnostic purposes, were analysed. DNA isolation was conducted using the E.Z.N.A.® Tissue DNA Kit. Amplification of the 36-InDelplex panel was performed, and Polymerase Chain Reaction products were analysed using the ABI PRISM® 3500 Genetic Analyzer and GeneMapper v.5.0 software. Data evaluation was performed using Microsoft® Excel.

Results revealed that the ID16 (rs16646) locus consistently generated peaks at 113.26 in all cat and dog samples, while the ID28 (rs2067147) locus produced a peak at 225.94 in one cow sample. These peaks, differing in size from those observed in human samples; indicate that the 36-InDelplex panel effectively discriminates animal DNA from human DNA. Additionally, peaks outside the expected loci ranges were detected in cow, sheep, goat, and dog samples, but no significant peaks were observed at other loci.

The findings demonstrate that the panel exhibits high specificity for human DNA with minimal cross-reactivity toward tested animal species, making it particularly valuable for forensic applications, especially given the frequent presence of animal biological materials at crime scenes. Although no positive results were observed in the tested species, further research with a broader range of species and larger sample sizes is essential to confirm these findings. A limitation of the study is the absence of primate samples, which could enhance the accuracy of specificity evaluation.