Review: Wildlife forensic genetics—Biological evidence, DNA markers, analytical approaches, and challenges

Wildlife-related crimes are the second most prevalent lawbreaking offense globally. This illicit trade encompasses hunting, breeding and trafficking. Besides diminishing many species and their habitats and ecosystems, hindering the economic development of local communities that depend on them, undermining the rule of law and financing terrorism, various cross-species transmissions (zoonoses) of pathogens, including COVID-19, can be attributed to wildlife crimes. Wildlife forensics applies interdisciplinary scientific analyses to support law enforcement in investigating wildlife crimes. Its main objectives are to identify the taxonomic species in question, determine if a crime has been committed, link a suspect to the crime and support the conviction and prosecution of the perpetrator. This article reviews wildlife crime and its implications, wildlife forensic science investigation, common forms of wildlife biological evidence, including DNA, wildlife DNA techniques and challenges in wildlife forensic genetics. The article also reviews the contributions of genetic markers such as short tandem repeat (STR) and mitochondrial DNA (mtDNA) markers, which provide the probative genetic data representing the bulk of DNA evidence for solving wildlife crime. This review provides an overview of wildlife DNA databases, which are critical for searching and matching forensic DNA profiles and sequences and establishing how frequent forensic DNA profiles and sequences are in a particular population or geographic region. As such, this review will contain an in-depth analysis of the current status of wildlife forensic genetics, and it will be of general interest to wildlife and conservation biologists, law enforcement officers, and academics interested in combating crimes against wildlife using animal forensic DNA methods.