O gene rbcL como barcode para identificação forense de Cannabis sativa

Geographic origin determination of Brazilian Cannabis sativa L. (Marihuana) by multi-element concentration

The Marihuana Polygon production of Cannabis sativa L. supplies the northeastern region of Brazil and represents 30% of the nation's market. The international trend of indoor cultivation is also occurring in Brazil, and the Brazilian Federal Police (BFP) has been increasing its apprehension of cannabis seeds sent by mail. The present work aims to assess the utility of the multi-element composition of different cannabis plant parts and soil samples where the plants were cultivated to determine their geographic origin. Statistical tools were applied to classification of marijuana samples from distinct geographic regions within northeastern Brazil, including indoor cultivated samples. The multi-element quantification was determined using inductively-coupled plasma - optical emission spectrometry (ICP-OES), and the data were compared by the Kruskal-Wallis H test, and subsequently, multiple discriminant analysis (MDA). The results of the multi-element concentration of cannabis plant samples were also subjected to a principal component analysis (PCA) and an orthogonal partial least squares discriminant analysis (OPLS-DA). The cannabis plant samples from the Marihuana Polygon could be clearly separated from those cultivated indoors, and the distance between them was detectable. The MDA revealed that phosphorus, calcium, magnesium, selenium, and arsenic concentrations were used as variables for this separation. Our results demonstrate that multi-element composition analysis can be used to indicate the origin or cultivation location of cannabis plants. Routine laboratory analyses consisting of multi-element composition combined with statistical analyses provide a reliable tool by which C. sativa movement, cultivation, and interdiction efforts in Brazil may be assessed.

Evaluation of two 13-loci STR multiplex system regarding identification and origin discrimination of Brazilian Cannabis sativa samples

According to the Brazilian Federal Police (BFP), the Brazilian Cannabis sativa illicit market is mainly supplied by drugs originated from Paraguay and Northeastern Brazil (Marijuana Polygon region). These two known routes, the increasing indoor cultivations (supported by online market), and drugs from Uruguay are also in BFP's sight. Forensic tools to aid police intelligence were published in the past years. In genetics, microsatellites have gained attention due to their individualization capability. This study aims to evaluate the effectiveness and efficiency of two STR multiplex systems previously proposed in 94 Cannabis sativa samples seized in Brazil. Principal coordinate analyses (PCoA), forensic parameters, and genetic structure analysis were executed. Both panels were effective in individualizing and origin discriminating all samples, and the system proposed in 2015 demonstrated better results. For this marker set, the probability of identity for a random individual is approximately one in 65 billion; also, the PCoA shows a clear genetic distinction among samples according to its origin. Bayesian inference populational structure analysis indicated a significant genetic diversity among seizure groups, matching with its origin. Overall, the STR multiplex systems were able to achieve its purpose in individualizing and differentiating, according to geographic region, Brazilian Cannabis sp. samples.

13-loci STR multiplex system for Brazilian seized samples of marijuana: individualization and origin differentiation

It is known that Cannabis in Brazil could either originate from Paraguay or be cultivated in Brazil. While consumer markets in the North and Northeast regions are maintained by national production, the rest of the country is supplied with Cannabis from Paraguay. However, the Brazilian Federal Police (BFP) has exponentially increased the seizure number of Cannabis seeds sent by mail. For this reason, the aim of the study was to assess the 13-loci short tandem repeat (STR) multiplex system proposed by Houston et al. (2015) to evaluate the power of such markers in individualization and origin differentiation of Cannabis sativa samples seized in Brazil by the BFP. To do so, 72 Cannabis samples seized in Brazil by BFP were analyzed. The principal coordinate analysis (PCoA) and probability identity (PI) analysis were computed. Additionally, the Cannabis samples' genotypes were subjected to comparison by Kruskal-Wallis H, followed by a multiple discriminant analysis (MDA). All samples analyzed revealed a distinct genetic profile. PCoA clearly discriminated the seizure sets based on their geographic origin. A combination of seven loci was enough to differentiate samples' genotypes, and the PI for a random sample is approximately one in 50 billion. The Cannabis samples were 100% correct as classified by Kruskal-Wallis H, followed by an MDA. The results of this study demonstrate that the 13-loci STR multiplex system successfully achieved the aim of sample individualization and origin differentiation and suggest that it could be a useful tool to help BFP intelligence in tracing back-trade routes.