The rbcL gene as a barcode tool for forensic identification of Cannabis sativa

Abstract

Cannabis sativa is one of the oldest species of domesticated plants and crops remains one of the most widely deployed and most used illicit drug in the world. There is a great diffi culty in identifying and differentiating the samples of Cannabis sp, complicating the correlation of the likely places illegal plantations, which would reveal traffi cking routes, criminal groups relate and distinguish those samples legal marketed as a drug, where cultivation is permitted. The main purpose of the DNA barcode is to provide a rapid and accurate identifi cation of organisms from a standard small region of the genome that help characterize and distinguish between species and individuals not to assign the identifi ed species. A candidate gene is the ribulose-1 ,5-bisphosphate carboxylase/oxygenase (rbcL), used as a DNA barcode system and present in chloroplast DNA of plants, and are responsible for producing large subunit of converting carbon dioxide and water into carbohydrates. Our goal is to develop an effi cient protocol for DNA extraction and sequencing ofrbcL gene for forensic analysis of seized samples of the Judicial Police. DNA samples from Cannabis sativa were characterized at ICCE/DGPTC/PCERJ and extracted using the DNeasy Plant Mini kit (Qiagen) at IPPGF/DGPTC/PCERJ. The material was transferred to LabFor/UFRJ and a fragment of 735 bprbcL gene was amplifi ed using a primer pair described in the literature as universal plants. The fragment was sequenced with the BigDye v3.1 protocol using ABI 3500 (Life Technologies). Comparisons of the sequences were performed in software Geneious (Biomatters). Our consensus sequence of 559 bp was compared to sequences that correspond to regions rbcL in Cannabis sativa deposited in GenBank, and observe the occurrence of polymorphisms (SNPs) between samples of the United States, Britain and China, suggesting that it is a genetic signature for forensic analysis.