The power of cannabis is written in its DNA, ‘rolled’ by ancient viruses which steered evolution, determining the production of its best known active principles: tetrahydrocannabinol (THC) and cannabidiol (CBD). 

The news arrives from the first detailed map of chromosomes of Cannabis Sativa, published in the magazine Genome Research, carried out by a group of coordinated researchers of the University of Toronto. 

This mapping will be useful to identify the exact position of the genes involved in the production of active molecules, allowing, for example, to improve the cultivation of plants intended for therapeutic use. 

The chromosome map of cannabis was already published in 2011 by the same research team, but the draft was still too fragmented and did not reveal the exact position of the genes on the chromosomes.

Today, a few years later, combining mapping with a new sequencing technique, the team has been able to reach the objective to finally carry out a detailed mapping of chromosomes.

The researchers discovered that the two genes responsible for the production of THC and CBD evolved from a single gene: both located on chromosome 6,  are surrounded by entangled, almost coiled sequences of Dna, by ancient viruses which colonized the plant millions of years ago.

The sequences of the viral genome, integrated in the plant Dna would have duplicated, becoming ‘mobile’ and hence being able to hop from one point to the other in the chromosomes. This invasion would have pushed the two genes to evolve in a different manner.

Another very useful discovery for the selection of future cultivations is the gene producing cannabichromene (CBC), another active substance which is less known even though it seems to have important pharmacological properties and could be responsible for some psychotropic effects in cannabis strains cultivated for therapeutic use.

Cannabis in short 

Cannabis can be divided in two species: Indica and Sativa. Phytocannabinoids are cannabinoids naturally present in the Cannabis plant, of which the best known are THC (Tetrahydrocannabinol), CBD (Cannabidiol) and CBG. 

The endocannabinoid system regulates the emotional and physiological states like stress, anxiety states, pain and inflammations. When we talk about the endocannabinoid system we are talking about a network of receptors present throughout the body, which follows the same circuits as the central nervous system. 

It is interesting to underline how cannabinoids are produced in nature only by Cannabis, by the human body and by some animals and that the endocannabinoid system interacts with the same cannabinoids, playing a fundamental role, like the ones already mentioned, to which we can add controlling the immune system and many other processes. The endocannabinoid system is made up of two main receptors, called CB1 and CB2. 

Endocannabinoids 

Cannabinoid receptors

Cannabinoids act mainly by binding to specific receptors which are located on the membrane surface of various cells, mainly placed in the brain and in the immune system. 

At today’s date 2 receptors have been identified, CB1 and CB2, even though it seems other possible cannabinoid receptors might exist. CBs are mainly located on the nervous cells of the CNS, while the CB2 receptors are mostly present in the immunocompetent cells.