A novel DNA profiling method for individual sample matching and its applications to wildlife diagnostics

The use of DNA analysis to match individual biological samples is central to many wildlife diagnostic applications and is particularly valuable in illegal wildlife trade investigations. However, although thousands of wildlife and plant species are affected by illegal trade, DNA profiling systems for individual identification exist for only a small number of taxa. This is primarily due to the need for extensive population reference data to enable conclusive interpretation of DNA profile matches, a key requirement in diagnostic contexts. Here, we introduce a novel approach that does not require population reference data to interpret an individual profile match and can be used with any set of genetic markers on a case-by-case basis. This approach, called 'heterozygote analysis for reference-free probability assessment' (HARP), is based on ultra-conservative match probability estimates using only heterozygote genotypes and assuming both alleles have a frequency of 0.5 in the population. HARP effectively eliminates the need for population reference data and standard marker panels and is therefore completely adaptable to any novel individual identification scenario. We demonstrate HARP using three case studies spanning a range of species and diagnostic scenarios.