Development of a targeted forensic test for the identification of Eurasian beaver DNA

Eurasian beaver (Castor fiber) has recently been reintroduced in Scotland after more than 400 years of extinction and in 2019 received legal protection; deliberate killing or disturbing beavers without a license is therefore now an offense. We present a validated polymerase chain reaction (PCR)-based Eurasian beaver identification test for use in forensic casework where persecution of Eurasian beaver is suspected. Primers were designed to target a 271 base pair region of the mitochondrial cytochrome b (Cytb) gene in Eurasian beavers, and positive amplicons were confirmed by sequence analysis. Validation was carried out across two laboratories in Scotland, and included studies on sensitivity, specificity, reproducibility, and robustness. The developed test reliably detects Eurasian beaver DNA to the lower limit of 0.1 pg DNA input and differentiates Castor fiber from other species, including congeners. In conclusion, the developed test was successfully optimized and validated to identify Eurasian beaver DNA and will be a valuable tool in wildlife forensic laboratories in cases of suspected persecution of Eurasian beavers

Honest sexual signalling mediated by parasite and testosterone effects on oxidative balance

Extravagant ornaments evolved to advertise their bearers' quality, the honesty of the signal being ensured by the cost paid to produce or maintain it. The oxidation handicap hypothesis (OHH) proposes that a main cost of testosterone-dependent ornamentation is oxidative stress, a condition whereby the production of reactive oxygen and nitrogen species (ROS/RNS) overwhelms the capacity of antioxidant defences. ROS/RNS are unstable, very reactive by-products of normal metabolic processes that can cause extensive damage to key biomolecules (cellular proteins, lipids and DNA). Oxidative stress has been implicated in the aetiology of many diseases and could link ornamentation and genetic variation in fitness-related traits. We tested the OHH in a free-living bird, the red grouse. We show that elevated testosterone enhanced ornamentation and increased circulating antioxidant levels, but caused oxidative damage. Males with smaller ornaments suffered more oxidative damage than those with larger ornaments when forced to increase testosterone levels, consistent with a handicap mechanism. Parasites depleted antioxidant defences, caused oxidative damage and reduced ornament expression. Oxidative damage extent and the ability of males to increase antioxidant defences also explained the impacts of testosterone and parasites on ornamentation within treatment groups. Because oxidative stress is intimately linked to immune function, parasite resistance and fitness, it provides a reliable currency in the trade-off between individual health and ornamentation. The costs induced by oxidative stress can apply to a wide range of signals, which are testosterone-dependent or coloured by pigments with antioxidant properties

Quantifying fenbendazole and its metabolites in self-medicating wild red grouse Lagopus lagopus scoticus using an HPLC–MS–MS approach

On red grouse estates in the UK the nematode parasite Trichostrongylus tenuis is often controlled by application of grit medicated with the anthelmintic fenbendazole (FBZ). To date, assessment of the efficacy has been inhibited by the inability to quantify uptake of FBZ by the birds. We have developed a simple and sensitive HPLC–MS–MS method for detecting and quantifying FBZ and its metabolites from a 300 mg sample of red grouse liver. This method could be used to improve the efficacy of medicated grit treatment by allowing the identification of conditions and application methods that optimize the uptake of FBZ. With the necessary modifications, our method will also be applicable to other wildlife species where self-medication is used for parasite control

STRoe deer: a validated forensic STR profiling system for the European roe deer (Capreolus capreolus)

European roe deer (Capreolus capreolus L.) are the most common game species in Europe, hunted for meat and trophies. Forensic investigations involving roe deer poaching may often benefit from an individual identification method to link a suspect to a specific incident. The current paper presents a forensically validated DNA profiling system for European roe deer called “STRoe deer”. This DNA profiling system consists of 12 novel unlinked tetra-nucleotide short tandem repeat (STR) loci and two sexing markers, with an allelic ladder to facilitate accurate genotyping. Validation results using 513 European roe deer samples collected from a single population from the Swiss Plateau demonstrated successful amplification of all 14 loci with as little as 0.05 ng of European roe deer DNA. Species-specificity tests showed that other members of the Cervidae family exhibited partial profiles and non-specific peaks, whereas most members of the Bovidae family showed just non-specific cross-species amplification products. Three different methods to calculate match probabilities for randomly sampled European roe deer genotypes resulted in median match probabilities ranging from 1.4 × 10−13 to 2.5 × 10−5. These methods accounted for possible population structure, occurrence of null alleles and individual relatedness. Based on these results, we conclude that STRoe deer is a robust genotyping system that should prove a valuable tool for individual identification and sexing of European roe deer to support criminal investigations