Cannabis: Origins, genotype, taxonomy, chemotypes

THE ORIGINS OF CANNABIS

Studies and scientific researches converge on the fact that cannabis was, for the first time, found on the Asian continent therefore we’ll take this notion for granted. Cannabis is native to Central Asia and perhaps the foothills of the Himalayas. Converging lines of evidence exist, including a centre of biological diversity, and biochemical data that supports this.

The genus Cannabis (Cannabaceae family) refers to three species, each with a very long history of domestication. The plants belonging to this genus are probably indigenous to the Asian continent where they grow preferably in places near bodies of water.This type of environment has often been chosen as a temporary settlement by nomadic human groups, before the discovery and spread of agricultural techniques. Cannabis species in the wild had an herbaceous attitude, growing in soils with high concentrations of nitrogen released by animal excrements and human activities. The long coexistence between man and Hemp led to a first domestication of the plant, which soon showed a surprising spectrum of possible uses. Hemp was used as a source of fabrics, as an edible plant (think, for example, of Iran where hemp seeds are roasted and salted and eaten as snacks. In Iran it is said that hemp seeds do very well to the heart, or in countries like Laos where the tops are used in the preparation of chicken soups) and as a medicinal and psychoactive plant (resins produced by secretory glandular trichomes). In recent times, hemp fibers have been used to produce bioplastic and antibacterial agents; furthermore, the trichomes are considered biofactories of phytochemicals with multiple biotechnological applications.

The extent of domestication of cannabis has been so persistent as to cause the disappearance of wild species: nowadays, the species Sativa belonging to the genus Cannabis are represented by a myriad of cultivated varieties, which occasionally escape cultivation and grow also in nature, giving life to shapes that lose some typical characteristics from those that are domesticated. For this reason the nomenclature of Cannabis has unstable bases and has been the subject of numerous taxonomic treatises.

It is widely accepted that Cannabis has two different species: Cannabis indica and Cannabis sativa. This was obviously the opinion of the great 18th century naturalist, Jean Baptiste Lamarck, but would the academic botanists agree with this statement today?Many classical botanists claim that cannabis is a polymorphic species based on the ability to interbreed amongst all its types. However, if this were true, hundreds of neotropical Gesnerias (Gesneriaceae, members of the African violets family) would constitute a single species because they all hybridize to each other producing a fertile offspring.

THE CONCEPT OF GENOTYPE

The term genotype refers to the set of all the genes that make up the DNA (gene supply) of an organism or a reference population. Each gene, individually and / or in a cooperative way, contributes differently to the development, physiology and functional maintenance of the entire organism. The set of externally observable characters is called phenotype. The genotype, by itself, does not define or determine the phenotype, rather it interacts with the environment, external or internal, in determining it.
Therefore two individuals with the same genotype (for example, homozygous twins) will not necessarily have an identical phenotype: this can be explained by the mechanisms of epigenetics, i.e.  that activity of gene regulation which, through chemical processes, does not directly alter the nucleotide sequence,  but can modify the phenotype of the individual or progeny: these epigenetic phenomena alter the physiological accessibility to the genome by molecular complexes responsible for gene expression, and therefore influence the functioning of the genes.

TAXONOMY : INDICA VS SATIVA

Cannabis indica was officially classified by the botanist Jean Baptiste Lamark who published the main differences between the types: Sativa, Indica, Ruderalis (Ruderalis is a subspecies of cannabis sativa).
Cannabis Indica as a relatively low and compact plant, conical in shape and with many branches. Practically the opposite of its sister C. Sativa, much taller, leaner and less branched. Another important morphological difference is in the foliage, C. Sativa has lighter, longer and thinner leaves, compared to those of C. Indica, wider and of a darker green.

 In addition to having a different appearance, the three species also differ in Cannabinoid content.
According to many, Cannabis Sativa produces more THC and less CBD (due to much selecting over the years to breed the CBD out of it) than Cannabis Indica which, in turn, has usually more CBD content and produces a more tranquil, centred, clear, and stimulating type of experience, one where you can be still present to yourself and function normally.
The paradox is that the landrace indica tend to contain less THC than the predominantly sativa strains.
Even many consumers report being more “stoned” and feeling less high when smoking an indica rather than a sativa. The high of a Cannabis indica is generally associated with a physical heaviness, it is particularly suitable for removing pain and promoting or inducing sleep and relaxation.

Cannabis sativa, on the other hand, is very energizing both physically and in the brain, accentuating creativity and favouring the onset of hallucinations, visions etc.  It is perfect for treating depression and in some cases ADHD.  Obviously we are all different therefore everyone can have a different experience.
Dr. Ethan Russo, neurologist and medical director of PHYTECS, a company focused on biotechnology applied to the human endocannabinoid system, says that today it makes no sense to talk about indica and sativa cannabis, rather we should talk about terpenes, since these are the molecules that determine the characteristic effects of each type of plant.

THE CHEMOTYPES OF CANNABIS

The term chemotype refers to a population of plants or microorganisms that, although belonging to the same species, differs  from all the other members of the species due to the chemical composition of the secondary metabolites. Small genetic differences that have no (or almost no) impact on morphology or anatomy can produce important changes in the chemical phenotype. The concept of chemotype is of particular interest in the field of aromatherapy, since different chemotypes can have very different therapeutic qualities. The belonging of a plant to a chemotype rather than to another, in some cases, can make the difference between a therapeutic essential oil and a toxic one.

To date we know several chemotypes of Cannabis:

1 Drug type predominant in THC

2 Hemp type predominant in CBD

3 Balanced type with 1:1 CBD / THC ratio

4 The zero type with very few cannabinoids

5 CBG type,  predominant in CBG, is the rarest cannabis chemotype.

This is a basic classification, but it has been  also possible to selectively isolate other chemotypes that express other titers of THCV, cannabidivarin, cannabichromene and even those that produce 100% of its cannabinoids such as cannabigerol, or others without cannabinoids.

Even domesticated varieties, which have evolved under the work of man, retain wild genes because DNA is a huge treasure trove of information. These genes remain dormant, that is, they do not express themselves phenotypically. In plant populations, but also in animals, there is always this reserve of genes in the event of a very large climate change. This genetic information could be expressed in the case of a crossing between two plants, especially between two populations that have remained separated for a very long period of time (we are talking about hundreds of years). In wild populations, on the other hand, the most widespread and common characteristics are precisely those that we will discard if they occur in the varieties we usually grow nowadays. When we cross two populations that have remained far away for a long time these wild characters re-emerge which , for the man, could be undesired, for example:

A very long vegetative cycle and a late flowering, very tall plants, unmanageable in indoor cultivations, or a low thc content compared to what we are used to today, or other things as a wide internodal distance, or hermaphroditic traits, while the type of plants usually cultivated are more compact, but this often results in poor vigour. The more vigourous a plant is, the longer the internodal distance between one leaf and the other will be, especially when it is cultivated and cared for by man, in a natural environment. The plants have longer internodes because if they received less water they would tend to shorten the distance between one leaf and the other and in addition the powerful roots of vigourous plants are able to make up for long periods of drought.
The absence of water and the abundance of sunlight causes the plant to temporarily change its shape, slowing down growth and assuming a more compact form. Many other features can appear whenever crossings are made. It is important to take this into account in a breeding and selection program. In general the wild characters prevail  in the progeny because the product of wild genes always has a greater influence on the game of inheritance.  A plant that for thousands of years has stabilized in an environment  by duplicating its DNA from generation to generation will always have the upper hand over a recent variety that genetically is not as strong and without  a stable gene pool.

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