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 <6.9 ×10-4), but may lack power for specific parentage questions, such as determining parentage of an offspring when one of the parent's genotypes is missing. Further, we have developed pipelines to support standardised SNP calling and decrease the chance of genotyping errors through the use of analytical workflows and synthetic positive controls. We expect the implementation of TigerBase will enhance enforcement of tiger trafficking cases and encourage compliance among captive tiger facilities, together contributing to combatting the illegal tiger trade.
Aim: The Sunda pangolin (Manis javanica) is the most widely distributed Asian pangolin species. It is one of the most trafficked mammals in the world, which not only negatively impacts wild Sunda pangolin populations, but also poses a potential disease risk to other species, including humans and livestock. Despite the imminent threat to the species’ survival and its prevalence in the wildlife trade, the phylogeography and evolution of the Sunda pangolin is not well understood. We aimed to investigate the species’ phylogeography across its distribution to improve our understanding of the species’ evolutionary history, elucidate any taxonomic uncertainties and enhance the species’ conservation genetic management and wildlife forensics applications. Location: Southeast Asia and southern China. Methods: We sequenced mtDNA genomes from 23 wild Sunda pangolins from Borneo and Peninsular Malaysia. We used these data in conjunction with previous generated mtDNA and nuclear datasets from across the species’ range to perform various phylogenetic and population genetic analyses. Results: We identified an evolutionarily distinct mtDNA lineage in north Borneo, which was estimated to be ~1.6 million years divergent from lineages in west/south Borneo and the mainland, comparable to the divergence time of the Palawan pangolin. There appeared to be mitonuclear discordance, with no apparent genetic structure across Borneo based on analysis of nuclear SNPs. Main conclusions: These findings are consistent with the ‘out of Borneo hypothesis’, whereby Sunda pangolins diversified in Borneo before subsequently migrating throughout Sundaland, and/or a secondary contact scenario between mainland and Borneo. We have elucidated possible taxonomic issues in the Sunda/Palawan pangolin complex, and highlight the critical need for additional georeferenced samples to accurately apportion its range-wide genetic variation into appropriate taxonomic and conservation units. Additionally, these data have improved forensic species identification testing involving these species and permit the implementation of geographic provenance testing in some scenarios.
Since 2011 the demand from China for the keratin casque from helmeted hornbills, so called red ivory, has increased significantly according to recent studies and has the potential to drive this species to extinction. Wildlife DNA Forensics is the field of science tasked not with expanding academic knowledge but with providing evidence for court in relation to wildlife crimes or for providing robust intelligence information to enforcement agencies in relation to trade routes for illegal wildlife products. In this pilot study, we examine the potential to recover DNA from the casques of the helmeted hornbill and evaluate how this genetic information could be used to better inform investigations into the illegal trade of helmeted hornbills.
Tigers are killed to supply a demand for many wildlife products despite a ban on commercial international trade. As populations decrease, products from substitute species (i.e. lions and leopards) have been fraudulently sold as tiger. DNA forensic techniques are needed to definitively identify tiger in order to secure prosecutions although this is complicated by the presence of numts. Therefore, we have developed and validated a CO1 genetic marker that preferentially amplifies the mtDNA CO1 region and excludes the nuclear CO1 pseudogene, which we expect to be of use in tiger forensic casework.
We developed a novel real-time PCR assay for rapid sexing in all three elephant species, which amplifies small fragments of the orthologous sexual chromosome zinc finger protein genes ZFX/ZFY (65 bp). This assay is a simple, inexpensive and reliable tool that is suitable for non-invasive DNA samples and can be incorporated into larger SNP panels for individual identification and population genetic studies.
Pangolins are the most trafficked mammal in the world, and all eight species are listed under CITES Appendix I. DNA-based wildlife forensic techniques are recognized as an important component of investigating a pangolin seizure. In particular, determining the species of pangolin in a seizure will 1) confirm the presence of pangolin to establish the legality of any trade, and 2) ensure appropriate laws are applied to their fullest extent in a prosecution. Furthermore, valuable intelligence data, such as determining the geographic provenance of samples, can be produced through analysis of pangolin seizures. Despite the immense scale of the pangolin trade, standardized wildlife forensic techniques for testing pangolin seizures are in their infancy. To address this, here, we present a standardized genetic marker suitable for species identification of all eight pangolin species, and outline practical strategies for sampling large-volume pangolin scale seizures. We assessed the repeatability, reproducibility, robustness, sensitivity and phylogenetic resolution of this species identification test. Critically, the assay was tested in four wildlife forensic laboratories involved in testing pangolins. Additionally, we demonstrated the test’s utility to conduct geographic provenance analysis of Phataginus tricuspis samples. We analysed five large-volume pangolin scale seizures in Malaysia, which elucidated key target species, poaching hotspots, and trafficking routes. Phataginus tricuspis was the most commonly identified species (88.8%) from the seizure samples, and 84.3% of these P. tricuspis individuals were likely sourced from western central Africa. We expect the implementation of the techniques presented in this paper will improve enforcement of pangolin trafficking crimes.
Proficiency tests are an important practice in forensic laboratories. However, the range of species available for wildlife forensic proficiency testing is currently limited, especially for laboratories in Africa and Asia where CITES-listed species are frequently tested. Here we present a proof of concept of a novel sample type for use in proficiency testing based on textured vegetable protein impregnated with the synthetic DNA of a target species. This sample can act as a substitute for animal tissue and can be shipped internationally without CITES and/or biosecurity permits. This simple procedure can help laboratories ensure compliance with international standards and guidelines.
A rapid allelic discrimination real-time polymerase chain reaction (qPCR) assay has been developed for the confirmation of lion (Panthera leo) or tiger (P. tigris) DNA. The method includes a low cost allele specific PCR assay designed for each SNP variant where the genotype is determined by incorporation and subsequent fluorescence of FAM or HEX following PCR. The described method was able to accurately and rapidly distinguish between the two species, and all three mitochondrial regions (16S, 12S and control region) performed equally well. The proposed real-time PCR assay can be applied for the accurate confirmation of either lion or tiger DNA that could be used by law enforcement agencies around the world as a tool to monitor illegal trade of tiger bones.
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Despite the critical need for non-invasive tools to improve monitoring of wildlife populations, especially for endangered and elusive species, faecal genetic sampling has not been adopted as regular practice, largely because of the associated technical challenges and cost. Substantial work needs to be undertaken to refine sample collection and preparation methods in order to improve sample set quality and provide cost-efficient tools that can effectively support wildlife management. In this study, we collected an extensive set of forest elephant (Loxodonta cyclotis) faecal samples throughout Gabon, Central Africa, and prepared them for genotyping using 107 single-nucleotide polymorphism assays. We developed a new quantitative polymerase chain reaction (PCR) assay targeting a 130-bp nuclear DNA fragment and demonstrated its suitability for degraded samples in all three elephant species. Using this assay to compare the efficacy of two sampling methods for faecal DNA recovery, we found that sampling the whole surface of a dung pile with a swab stored in a small tube of lysis buffer was a convenient method producing high extraction success and DNA yield. We modelled the influence of faecal quality and storage time on DNA concentration in order to provide recommendations for optimized collection and storage. The maximum storage time to ensure 75% success was two months for samples collected within 24 hours after defecation and extended to four months for samples collected within one hour. Lastly, the real-time quantitative PCR assay allowed us to predict genotyping success and pre-screen DNA samples, thus further increasing the cost-efficiency of our approach. We recommend combining the validation of an efficient sampling method, the build of in-country DNA extraction capacity for reduced storage time and the development of species-specific quantitative PCR assays in order to increase the cost-efficiency of routine non-invasive DNA analyses and expand the use of next-generation markers to non-invasive samples.
The illegal ivory trade continues to drive elephant poaching. Large ivory seizures in Africa and Asia are still commonplace. Wildlife forensics is recognised as a key enforcement tool to combat this trade. However, the time and resources required to effectively test large ivory seizures is often prohibitive. This limits or delays testing, which may impede investigations and/or prosecutions. Typically, DNA analysis of an ivory seizure involves pairing and sorting the tusks, sampling the tusks, powdering the sample, decalcification, then DNA extraction. Here, we optimize the most time-consuming components of this process: sampling and decalcification. Firstly, using simulations, we demonstrate that tusks do not need to be paired to ensure an adequate number of unique elephants are sampled in a large seizure. Secondly, we determined that directly powdering the ivory using a Dremel drill with a high-speed cutter bit, instead of cutting the ivory with a circular saw and subsequently powdering the sample in liquid nitrogen with a freezer mill, produces comparable results. Finally, we optimized a rapid 2 -h decalcification protocol that produces comparable results to a standard 3-day protocol. We tested/ optimised the protocols on 33 raw and worked ivory samples, and demonstrated their utility on a case study, successfully identifying 94% of samples taken from 123 tusks. Using these new rapid protocols, the entire sampling and DNA extraction process takes less than one day and requires less-expensive equipment. We expect that the implementation of these rapid protocols will promote more consistent and timely testing of ivory seizures suitable for enforcement action.
Illegal hunting is a major threat to the elephants of Africa, with more elephants killed by poachers than die from natural causes. DNA from tusks has been used to infer the source populations for confiscated ivory, relying on nuclear genetic markers. However, mitochondrial DNA (mtDNA) sequences can also provide information on the geographic origins of elephants due to female elephant philopatry. Here, we introduce the Loxodonta Localizer (LL; www.loxodontalocalizer.org), an interactive software tool that uses a database of mtDNA sequences compiled from previously published studies to provide information on the potential provenance of confiscated ivory. A 316 bp control region sequence, which can be readily generated from DNA extracted from ivory, is used as a query. The software generates a listing of haplotypes reported among 1917 African elephants in 24 range countries, sorted in order of similarity to the query sequence. The African locations from which haplotype sequences have been previously reported are shown on a map. We demonstrate examples of haplotypes reported from only a single locality or country, examine the utility of the program in identifying elephants from countries with varying degrees of sampling, and analyze batches of confiscated ivory. The LL allows for the source of confiscated ivory to be assessed within days, using widely available molecular methods that do not depend on a particular platform or laboratory. The program enables identification of potential regions or localities from which elephants are being poached, with capacity for rapid identification of populations newly or consistently targeted by poachers.
Rhinoceros (rhinos) have suffered a dramatic increase in poaching over the past decade due to the growing demand for rhino horn products in Asia. One way to reverse this trend is to enhance enforcement and intelligence gathering tools used for species identification of horns, in particular making them fast, inexpensive and accurate. Traditionally, species identification tests are based on DNA sequence data, which, depending on laboratory resources, can be either time or cost prohibitive. This study presents a rapid rhino species identification test, utilizing species-specific primers within the cytochrome b gene multiplexed in a single reaction, with a presumptive species identification based on the length of the resultant amplicon. This multiplex PCR assay can provide a presumptive species identification result in less than 24 hours. Sequence-based definitive testing can be conducted if/when required (e.g. court purposes). This work also presents an actual casework scenario in which the presumptive test was successfully utlitised, in concert with sequence-based definitive testing. The test was carried out on seized suspected rhino horns tested at the Institute of Ecology and Biological Resources, the CITES mandated laboratory in Vietnam, a country that is known to be a major source of demand for rhino horns. This test represents the basis for which future 'rapid species identification tests' can be trialed.
Abstract The continuing decline in forest elephant (Loxodonta cyclotis) numbers due to poaching and habitat reduction is driving the search for new tools to inform management and conservation. For dense rainforest species, basic ecological data on populations and threats can be challenging and expensive to collect, impeding conservation action in the field. As such, genetic monitoring is being increasingly implemented to complement or replace more burdensome field techniques. Single‐nucleotide polymorphisms (SNPs) are particularly cost‐effective and informative markers that can be used for a range of practical applications, including population census, assessment of human impact on social and genetic structure, and investigation of the illegal wildlife trade. SNP resources for elephants are scarce, but next‐generation sequencing provides the opportunity for rapid, inexpensive generation of SNP markers in nonmodel species. Here, we sourced forest elephant DNA from 23 samples collected from 10 locations within Gabon, Central Africa, and applied double‐digest restriction‐site‐associated DNA (ddRAD) sequencing to discover 31,851 tags containing SNPs that were reduced to a set of 1,365 high‐quality candidate SNP markers. A subset of 115 candidate SNPs was then selected for assay design and validation using 56 additional samples. Genotyping resulted in a high conversion rate (93%) and a low per allele error rate (0.07%). This study provides the first panel of 107 validated SNP markers for forest elephants. This resource presents great potential for new genetic tools to produce reliable data and underpin a step‐change in conservation policies for this elusive species.
Rhinoceros (rhino) numbers have dwindled substantially over the past century. As a result, three of the five species are now considered to be critically endangered, one species is vulnerable and one species is near-threatened. Poaching has increased dramatically over the past decade due to a growing demand for rhino horn products, primarily in Asia. Improved wildlife forensic techniques, such as validated tests for species identification of seized horns, are critical to aid current enforcement and prosecution efforts and provide a deterrent to future rhino horn trafficking. Here, we present an internationally standardized species identification test based on a 230 base pair cytochrome-b region. This test improves on previous nested PCR protocols and can be used for the discrimination of samples with <20pg of template DNA, thus suitable for DNA extracted from horn products. The assay was designed to amplify water buffalo samples, a common ‘rhino horn’ substitute, but to exclude human DNA, a common contaminant. Phylogenetic analyses using this partial cytochrome-b region resolved the five extant rhino species. Testing successfully returned a sequence and correct identification for all of the known rhino horn samples and vouchered rhino samples from museum and zoo collections, and provided species level identification for 47 out of 52 unknown samples from seizures. Validation and standardization was carried out across five different laboratories, in four different countries, demonstrating it to be an effective and reproducible test, robust to inter laboratory variation in equipment and consumables (such as PCR reagents). This is one of the first species identification tests to be internationally standardized to produce data for evidential proceedings and the first published validated test for rhinos, one of the flagship species groups of the illegal wildlife trade and for which forensic tools are urgently required. This study serves as a model for how species identification tests should be standardized and disseminated for wildlife forensic testing.
Wildlife crime continues unabated contributing to the extinction or near extinction of many plant and animal species. Species identification is a key tool in the enforcement of national legislation. If no morphology exists, comparison of DNA sequences generated from a mitochondrial gene are compared to those on a reference database, commonly GenBank. Sequences up-loaded to GenBank are unregulated and can lead to uncertainty with the adequacy of this DNA sequence repository for identification in a forensic context. We propose the establishment of ForCyt as a fully-regulated database of species that are commonly encountered in forensic investigations. The establishment of ForCyt will allow confidence in future species identification; something that is an absolute requirement to ensure high quality forensic science.
Conservation management of species distributed across fragmented habitats requires consideration of population genetic structure and relative levels of genetic diversity throughout the relevant geographical range. The Golden Eagle Aquila chrysaetos is monitored within Scotland to ensure its survival in the face of land‐use pressure, persecution and future climate change. In this study we constructed DNA profiles for 271 individual birds using a collection of over 1600 moulted feathers collected from 148 territories, representing 34% of known Scottish territories in the largest population genetic study of Golden Eagles undertaken to date. The results, based on data from 10 nuclear microsatellite loci, revealed previously unreported genetic structure between the islands of the Outer Hebrides and the rest of Scotland (FST = 0.03), together with evidence of reduced genetic diversity in the Outer Hebridean population compared with mainland Scotland. Analysis of gene flow supports a hypothesis of limited, predominantly male‐mediated, dispersal from the Outer Hebrides to mainland Scotland. The persistence of this pattern is discussed with respect to variation in population density and persecution pressure across Scotland. A finding of non‐random mating within the Outer Hebrides is interpreted as evidence of natal philopatry that was revealed by more intensive sampling in these islands, and is likely to be accentuated by the apparent degree of isolation of the islands from the rest of Scotland.
The pygmy hippo is an Endangered mammal endemic to West Africa, of which only 2,000–3,000 are left in the wild. Until now genetic resources to conduct monitoring of wild populations and to facilitate captive breeding have been lacking. In this study we used restriction-site associated DNA sequencing of five pygmy hippo samples to generate 1,619 high confidence candidate single nucleotide polymorphisms (SNPs) suitable for population genetic analysis. A subset of 10 of SNPs generated were validated via resequencing with 100 % success rate and through the use of KASPar DNA probes (Kbiosciences) with 90 % success rate. To facilitate future research we present the list of 1,619 SNPs ranked according to mean genotype confidence and mean coverage.
The confirmed presence of alien North American beavers in some regions of Eurasia may compete with and hinder the successful recolonisation of the native Eurasian species back to its former range. Distinguishing the two species in the field can be problematic, time consuming and expensive, thereby potentially limiting appropriate conservation actions. Here, a rapid and inexpensive genetic SNP assay is described that can separate the two species from either non-invasively collected samples or samples taken directly from restrained individuals. We applied these new genetic assays to free-living beavers of unknown origin sampled in Scotland.