Journal Article

Broad-Scale Genetic Diversity of Cannabis for Forensic Applications

Jan, Catherine, Goudet, Jérôme, Fumagalli, Luca, Bienert, Friederike, Dufresnes, Christophe

2017

Overview

Cannabis (hemp and marijuana) is an iconic yet controversial crop. On the one hand, it represents a growing market for pharmaceutical and agricultural sectors. On the other hand, plants synthesizing the psychoactive THC produce the most widespread illicit drug in the world. Yet, the difficulty to reliably distinguish between Cannabis varieties based on morphological or biochemical criteria impedes the development of promising industrial programs and hinders the fight against narcotrafficking. Genetics offers an appropriate alternative to characterize drug vs. non-drug Cannabis. However, forensic applications require rapid and affordable genotyping of informative and reliable molecular markers for which a broad-scale reference database, representing both intra- and inter-variety variation, is available. Here we provide such a resource for Cannabis, by genotyping 13 microsatellite loci (STRs) in 1 324 samples selected specifically for fibre (24 hemp varieties) and drug (15 marijuana varieties) production. We showed that these loci are sufficient to capture most of the genome-wide diversity patterns recently revealed by NGS data. We recovered strong genetic structure between marijuana and hemp and demonstrated that anonymous samples can be confidently assigned to either plant types. Fibres appear genetically homogeneous whereas drugs show low (often clonal) diversity within varieties, but very high genetic differentiation between them, likely resulting from breeding practices. Based on an additional test dataset including samples from 41 local police seizures, we showed that the genetic signature of marijuana cultivars could be used to trace crime scene evidence. To date, our study provides the most comprehensive genetic resource for Cannabis forensics worldwide.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Agricultural industry / Biodiversity / Bioinformatics / Biology and Life Sciences / Breeding / Breeding methods / Cannabis / Cannabis (Plant) / Cannabis - genetics / Cannabis sativa / Conservation biology / Crime / Crops / Cultivars / Domestication / Drug abuse / Drug Trafficking / Drugs / Ecology / Economic conditions / Evolution / Flowers & plants / Forensic engineering / Forensic science / Forensic sciences / Genetic aspects / Genetic diversity / Genetic Markers - genetics / Genetic resources / Genetic structure / Genetic Variation - genetics / Genetics / Genomes / Genotype / Genotyping / Haplotypes / Hemp / Laboratories / Licenses / Life Sciences / Loci / Marijuana / Medicine and Health Sciences / Microsatellite Repeats - genetics / Multiculturalism & pluralism / Multivariate analysis / People and Places / Physical Sciences / Physiological aspects / Plant breeding / Plants (botany) / Police / Population / Research and Analysis Methods / Seeds / Seizures / Short tandem repeats / Social Sciences / Taxonomy / Tetrahydrocannabinol