TigerBase: A DNA registration system to enhance enforcement and compliance testing of captive tiger facilities

• Published in: Forensic science international : genetics 2025-01, Vol.74, p.103149, Article 103149
• Main Authors: Ewart, Kyle M., Sitam, Frankie T., Giarat Ali, Nur Alizati Nabila Binti, Ogden, Rob, Morgan, Kelly I., Tran, Hieu M., Bui, Thanh P.T., Nguyen, Truong Q., Nguyen, Son G., Rosli, Norsyamimi, Penchart, Kitichaya, Ouitavon, Kanita, McEwing, Ross
• Format: Article
• Language: English
• Subjects: Animals; Conservation of Natural Resources - legislation & jurisprudence; DNA - genetics; DNA Fingerprinting; DNA register; Female; Genotype; Illegal wildlife trade; Panthera tigris; Polymorphism, Single Nucleotide; SNP genotyping; Tigers - genetics; Validation; Wildlife forensic science
• ISSN: 1872-4973; 1878-0326; 1878-0326
• DOI: 10.1016/j.fsigen.2024.103149

The illegal trade in tigers (Panthera tigris) and their derivatives, such as bones, teeth and pelts, is a major threat to the species’ long-term persistence. As wild tiger populations have dwindled, a large proportion of trafficked tiger products now derive from captive breeding facilities found throughout Asia. Moreover, wild tigers have been poached and laundered into captive facilities, then falsely designated as captive-bred. The establishment of a DNA registration system is recognized as a key tool to monitor compliance of captive facilities, support tiger trade investigations and improve prosecution outcomes. Here, we present a standardised wildlife forensic DNA profiling system for captive tigers called TigerBase. TigerBase has been developed in four South-East Asia countries with captive tiger facilities: Malaysia, Vietnam, Thailand and Lao PDR. TigerBase DNA profile data is based on 60 single nucleotide polymorphism (SNP) markers, genotyped using two different TaqMan®-based approaches: OpenArray® chip (capable of genotyping 60 SNPs for 48 samples in a single chip), and singleplex TaqMan® assays (capable of genotyping one SNP for one sample per reaction). Of the 60 SNPs, 53 are autosomal nuclear markers, suitable for individualisation and parentage applications, two are sex-linked markers, suitable for sexing, and five are mtDNA markers, suitable for maternal subspecies identification. We conducted a series of validation experiments to investigate the reliability and limitations of these SNP genotyping platforms. We found that the OpenArray® chip platform is more appropriate for generating reference data given its greater throughput, while the singleplex TaqMan® assays are more appropriate for genotyping lower quality casework samples, given their higher sensitivity and throughput flexibility. Only 19 autosomal nuclear markers were validated as singleplex TaqMan® assays, which generally provides ample power for individualisation analysis (probability of identity among siblings was