Direct PCR-FINS: Wildlife species identification without DNA extraction

Abstract

Forensically informative nucleotide sequencing (FINS) is commonly used in forensic laboratories worldwide for wildlife species identification. Recently direct PCR – DNA amplification without prior DNA extraction – has been gathering attention in the human forensic community due to its high efficiency, but it has never been applied to non-human forensic investigation. Therefore, we aimed to evaluate the possibility and efficiency of using direct PCR-FINS for species identification from various types of forensically relevant animal samples. Eight biological evidence types (hair, muscle tissue, bloodstain, bone, ear, skin, urine, and feces) from three common crime-related animals (tiger, white rhino, and Asian elephant) were analyzed with the three-step direct PCR-FINS method: direct PCR amplification of target DNA with 16S rRNA and cytochrome b universal primers, sequencing, and database searching (BLAST). All sample types were successfully amplified using direct PCR-FINS method and provided the expected PCR products. Each amplicon sequence and its relevant animal species were completely matched using BLAST, meaning that the species of the samples were correctly identified. In conclusion, the ‘direct PCR-FINS method’ is rapid, reliable, and meets the requirement of international forensic organizations.