Cannabis plant and it’s genetics

    29-Feb-2020
Dr Sona A Pungavkar
People, who use Cannabis regularly, often find that they feel a mild effect while using a joint, and at other times, they feel completely blown away by the “quality of the high” they experience. The taste and smell as well as the “feel of the high” wants them to have the latter experience again and again. They may not be aware but it is probably something to do with the genetics of that particular Cannabis plant strain. As already known, humans, have 22 pairs of chromosomes with 2 sex chromosomes, making a genome of 46 chromosomes. Females have two X chromosomes and males have an X and a Y chromosome. This constitutes the genotype. The physical expression of these collective genes is called as the phenotype, such as height, color of eyes, lack of certain enzymes etc.
Similarly, in the Cannabis plant, 9 pairs of chromosomes are found, with a pair of sex chromosomes. The major differences, which result in the Cannabis plant, as a result of the genetic variations, include which enzymes are present and which cannabinoids are predominating in a particular strain of the plant. For example, when an enzyme called tetrahydrocannabinolic acid synthase (THCAS) is expressed at higher levels, there is a resultant increase in the amount of THC, while another strain which expresses the enzyme, cannabidiolic acid synthase (CBDAS) at higher levels, is expected to have higher levels of CBD. As a result, these two strains will have different effects on an individual, such as the first strain causing a desirably elevated “high”.
Another factor, which influences the content of the plant, is the environment in which it is grown. Two plants with the same genetic signature are likely to have different colors, shapes, smells as well as the amount of cannabinoids, when grown in different places with different climactic conditions. So, the final result is a combination of the genetic code of the plant and the environment in which it is grown.
Cannabis was earliest found in North Indian mountains and some tropical countries. Two varieties, indica and sativa, became popular on the basis of the geographical locations and climatic variations. A third, lesser known variety, is called as ruderalis. These three constitute the pure varieties.
Cannabis Sativa grows in warmer climate and is found abundantly in South East Asia. These plants are tall, reaching upto 4.5 metres in height, when fully grown. The plants have long distances between nodes as well as long branches. The leaves are large with narrow blades. The vegetation cycle can be upto 6 months, making it a difficult plant to grow indoors. The THC content is lower than that of Indica and it has a higher CBD to THC ratio. This strain has been known to have an uplifting effect on the mind, introspective effect, energizing effect on the body, and stimulation of the creativity. Hence, it is used to alleviate depression, experience spiritual effects, to relieve fatigue and pain. It is also used by artists and writers to stimulate creativity. Because of it’s stimulating effects, it is used as a day time product. It has also been used as a source of fibre and seed oil.
Cannabis Indicais another well known strain, originating in Northern Indian mountains, Afghanistan and Morocco. The name ‘Indica’ is traced to the Indian subcontinent, with combination ‘India’ and ‘Cannabis’ used to name it. These plants are shorter, growing upto 2-3 feet. The internodal distance is short and the leaves are fat and wide. The flowering cycle is 8 to 12 weeks. The short height and the short growth cycle, make it feasible, to grow the indica plant indoors. The THC and CBD contents are higher than the Sativa strain, with higher THC to CBD ratio. Hence, it is known to give a ‘stoned’ feeling. In contrast to the stimulating effects of Sativa, Indica has a relaxing and sedating effect. It has pain and relief and muscle relaxing properties and hence finds various uses in treatment of anxiety, chronic pain, muscle spasms, fibromyalgia, insomnia etc. Because of the sedative and relaxing effects, it is mainly used in the night time.
Cannabis Ruderalis is not well known and is an auto-flowering plant, which can grow in harsh climates. Hence, it is found in Central/Eastern Europe and Central Asia and Russia. These plants are short and can grow from 1 to 2.5 feet. The flowering cycle is induced based on the maturity and can be between 21 to 30 days, unlike the long periods seen in Sativa and Indica. The THC content is low and hence, using it for creation of hybrids, with unique smells and colors, is the way to go.
Hybrid Cannabis strains have developed as a result of interbreeding of these three pure varieties to enhance certain characteristics of each strain, though combinations of sativa and indica are favoured, over the use of ruderalis. The final product may contain the pure varieties in different ratios and hence numerous combinations are possible.
Several hybrid varieties are known and are differentiated by the way they are produced.
Inbred Line (IBL), as the name indicatesis a variety of hybrids, which is produced by selectively inbreeding of pure strains. This is done to preserve a certain characteristic in a known strain. The variations in the resultant plant will be smaller in number and there will be no change in the appearance of the plant.
F1 Hybrid is the result of crossing of two IBLs. F1 hybrids grow faster and have a higher yield than both the primary IBLs and also have variations between the seedlings.
F2, F3, F4 Hybrids result as inbreeding between the hybrids is propagated. When two F1 hybrids are crossed, the seedling is labelled as F2 hybrid. F3 hybrids are the result of crossing of two F2 hybrids and so on. The variations increase as the number increases.
Synthetic Varieties of Cannabis strains are also possible. It results from interbreeding of few IBLs and use a mix of the seeds, though this is not a common method.
To think of it, there is no limit to the different Cannabis strains that can be made available and each strain would have it’s own genetic code and phenotypic expression, which would include a unique flavour (taste and smell), color and appearance and above, a unique effect in every individual, after use.
The author is a Cannabis researcher, a senior radiologist and Vice President, Cannabis Health and Sciences.
The article does not reflect the views of the newspaper in any way