Forensic validation of a SNP and INDEL panel for individualisation of timber from bigleaf maple (Acer macrophyllum Pursch). (May 2020) - Dormontt, E.E.
Highlights: Illegal logging is one of the world's largest illicit trades, with few prosecutions. There are a lack of forensic identification tests for timber. We report on the development of a DNA assay for bigleaf maple ( Acer macrophyllum ) that can be used to assign timber materials to their tree of origin. Population (n = 394) screened with 131 SNP and INDEL markers providing high levels of confidence of association ( FST -corrected P ID = 1.785 × 10 −25 ). A full forensic validation process was conducted by adapting for timber the SWGDAM guidelines developed for human identification assays. Abstract: Illegal logging is one of the largest illicit trades in the world, with high profits and generally low risks of detection and prosecution. Timber identification presents problems for law enforcement as traditionally used forensic methods such as wood anatomy and dendrochronology are often unable to confidently match wood evidence to the remains of illegally felled trees. Here we have developed and validated a set of genetic markers for individualisation in bigleaf maple ( Acer macrophyllum ), a high value timber species often felled illegally in the USA. Using 128 single nucleotide polymorphisms and three insertion/deletion markers developed through massively parallel sequencing, 394 individuals were genotyped on the MassARRAY® iPLEX™ platform (Agena Bio-science™, San Diego, USA) to produce a population reference database for the species. We demonstrate that the resulting DNA assay is reliable, species specific, effective at low DNA concentrations (<1 ng/μL) and suitable for application to timber samples. The P ID for the most common profile, calculated using an overall dataset level FST -correction factor, was 1.785 × 10 −25 and P ID-SIB across all individuals (treated as a single population) was 2.496 × 10 -22 . The further development of forensic identification assays for timber species has the potential to deliver robust tools for improved detection and prosecution of illegal logging crimes as well as for the verification of legality in reputable supply chains.