We interviewed Dr. Michele Di Nunzio and Dr. Carme Barrot, professors at the Faculty of Medicine of the University of Barcelona and members of the Laboratory of Forensic Genetics of the UB.

They have participated in the validation of an innovative technique that makes it possible to genetically identify seized Cannabis sativa plants to determine whether the samples come from the same clone and to relate possible origins of the samples and their classification as legal or illegal plants.

The recording of this information in a database, linked to information on the location of their seizure, can be of great use in future investigations, allowing the linking of confiscated plants and their distribution networks.

What does your project consist of?

Carme Barrot (CB): We are a forensic genetics laboratory, mainly human. When Dr Di Nunzio arrived with this project, we decided to use techniques based on molecular biology and current forensic genetics techniques used in human identification to apply them to plants.

Michele Di Nunzio (MDN): Since 2018, we have been studying and analysing genetic markers of Cannabis sativa to identify samples, discriminate individuals, determine the biogeographical origin of a plant and determine whether it is a legal or illegal plant.

How do you do this in order to determine whether a plant is legal or illegal?

(MDN): Cannabis sativa is a monospecific plant, meaning it has only one species. But the result of years of crossbreeding different cannabis strains has produced thousands of hybrids. Every day, growers try to find new hybrids in which they try to fix the characteristics of the plant they like (smell, taste, effects, etc.).

The concept of legal and illegal is dictated by the European Union and each country has its own laws that determine which plants are illegal. The legality or illegality of a plant is given by a psychotropic molecule produced by Cannabis sativa. The EU says that plants with more than 0.2% tetrahydrocannabinol (THC) are illegal, while plants with less than 0.2% THC are legal. Currently, to determine THC concentrations, the only valid techniques are toxicological. We, with genetics, can help these toxicology techniques and provide a lot of information, both on the forensic and industrial side.

What information can you provide?

(MDN): Plants that are confiscated and stored in the wrong way can accelerate the processes of decomposition and THC degradation. Therefore, we do not know the real concentrations of this molecule and cannot really determine whether it is legal or illegal. With genetics we can identify plants that have previously been confiscated, we can compare them with each other and inform judges, prosecutors, police that a certain illegal plant was previously confiscated in a specific part of the world. Concretely helping in connecting drug trafficking routes.

Cannabis sativa can also be legal.

(MDN): Yes, they are plants that can be used in the textile industry, food industry and so on. The EU allows the sowing of authorised seeds to reproduce the plant, but does not allow the cloning of plants. If the police investigate a legal plantation, with toxicological techniques, they cannot know if these plants are clones of other plants. We, knowing the genetic profile of the legal plants, can say that these plants that have been planted have a lineage with the mother plant from which these authorised seeds come.

(CB): These legal plants can also be used, if appropriate, at a medical level, especially with cancer patients to avoid side effects. Our technology determines the identity of a plant, regardless of the percentage of THC. It is therefore a tool that can also be used in the medical industry for the production of safer plants that can benefit the health of patients.

What are the advantages of this technology?

(MDN): We can give a biological entity to these plants. We can connect different plants and trace drug trafficking lines. In this way, we could help both national and international police, judges, and prosecutors investigating drug trafficking cases. We could also help the European industry by isolating genetic profiles of legal plants. From these legal plants, seeds will be produced that will have a genetic part equal to the mother plant. In this way, it will be much easier to determine the genetic profile of legal plants. It is like in a maternity test. If I know the genetic profile of the legal mother, I can tell if these ‘daughter’ plants belong to the legal mother plant.

On the other hand, the identification of cannabis chloroplast markers is very important to determine whether a plant comes from one country or another. Or we can even define whether this plant has been cultivated in one city or another.

(CB): When you analyse seized chemicals, you expect that when they are stored and preserved they will stay the same, but that is not the case. We could help them in situations where preservation has not gone well, for whatever reason.

How can you help draw lines to identify drug trafficking networks?

With a database of Cannabis sativa plants. Imagine that a marijuana plant is confiscated in Barcelona. A toxicological analysis has to be done on this plant to determine the illegal THC levels. At the same time, I can do a genetic analysis that would give me a unique profile of this plant. If I take this profile and put it in my database, I can save it for future research because data does not take up space like a plant. If tomorrow a plant is confiscated in Madrid, the genetic profile can be compared with my database. And if I have a match between the two plants, we can tell the people who are investigating that the plant with the same genetic profile is moving between Madrid and Barcelona.

It is a revolutionary technology that can mark a before and after in the investigation of marijuana trafficking.

(CB): Yes, I think it is a very interesting project because this technology can provide much more information than can be obtained today through toxicology alone. We don’t want to give more work to the police. The tool serves to provide information that could help them solve cases and link them together.

MORE ABOUT… Michele Di Nunzio and Carme Barrot

The best invention in history?
Carme Barrot (CB): The wheel.
Michele Di Nunzio (MDN): The PCR.

What would you like to see in the future?
(CB): This project fully functioning.
(MDN): To see that our research is useful and recognised.

One future development that scares you?
(CB): Artificial intelligence.
(MDN): The current world political situation.

A point of reference?
(CB): Charles Darwin.
(MDN): My father, a great geneticist. I will also say Gregor Mendel.

What could be done to achieve equality between men and women?
(CB): I always value the knowledge and attitude they have.
(MDN): To continue working in harmony and without differences between men and women.

Transfer is important for…
(CB): That people value the research we do.
(MDN): It is important because that is how you learn, and learning is improving.