Cannabis: Marijuana, hemp and its cultural history. By Daniela Vergara

Daniela_Vergara_1Cannabis is a genus of flowering plants (Angiosperms) that belongs to the order Rosales and family Cannabacea. .  The Angiosperms clade is quite possibly the most diverese plant group existing on Earth, with at least 250,000 living species if not more [1, 2]. The family Cannabaceae is composed of 10 different genera and approximately 100 species along with Hops (genus Humulus) [3, 4]. The number of species that compose the genus Cannabis is debated among scientists, some claim that it is composed of at least two species (C. sativa and C. indica) [5], while others claim that it is composed of one species (C. sativa) [6].  A third species or grouping C. ruderalis, is known but does not have as big importance as C. sativa and C. indica because it is a smaller plant and seems to not produce psychedelic or medical compounds. C. ruderalis appears to not depend on light cues from the sun to flower (early flowering).

Cannabis plants differ in numerous phenotypic aspects.  For example, there is a huge diversity of secondary compounds like terpenoids, which give the plant its smell and the cannabinoids, which give the plant its psychedelic properties. The production of these secondary metabolites is mostly found in the flower (buds) of the female plant [7]. The production of these metabolites vary between strains, both the cannabinoids[5]and the terpenoids [8, 9].

Marijuana is the vernacular for Cannabis,which is often consumed in a variety of forms such as smoking, vaporizing, or eating.  Marijuana includes the groups C. sativa and C. indica. Hemp is a type of Cannabis that is used to extract fiber, aliments, wax and oil. Hemp is associated to C. sativa plants, even though scientific studies have found that hemp and marijuana strains appear to be more closely related within than between them [10]. However, these studies only included four individuals and with this extremely low sample size few decisive conclusions can be addressed. Hemp has low THC (Tetrahydrocannabinol), which is a compound produced by the plant responsible for the psychoactive effects. In the US in order for a Cannabis plant to be cataloged as hemp it must have less than (<) 0.3% THC, which is an arbitrary number with no biological significance.

Further research is necessary to establish the differences between the Cannabis groups, between marijuana and hemp and between the commonly used marijuana strains research that is currently conducted by investigators at CGRI.

Cannabis appears to be one of the oldest cultivated plants [11], and even though a topic of controversy among scientist, some believe the plant is original to Asia [11, 12]. The Chinese are one of the cultures that started cultivating Cannabis since the Neolithic times for fiber and medicine [11]. Cannabis was also used for rope and medicine in Ancient Egypt approximately 2350 B.C.  Knowledge of its medicinal use quickly spread throughout the ancient world appearing in places such as Greece and Rome.[12]. Still, the spread of Cannabis appears to have reached Europe around the 13th century. Other ancient cultures that used Cannabis include India, Mesopotamia and the Greeks and Romans.  The Indians used Cannabis at around 1600B.C. for different purposes including release of anxiety [12]. In Mesopotamia Cannabis was used for its psychoactive properties but also as insecticide, for fiber and as medicine administered orally and cutaneously [12]. Finally, the Greeks have documented the psychoactive effects of Cannabis since approximately 450 B.C.

Our Cannabis research has direct import for industry, medicine and agriculture. The cultivation of hemp is increasing and has a diversity of potential uses such as fuel, paper, and insulation among many others. Second, medical marijuana has been used in multiple settings and numerous illnesses and even has promising uses including reducing nausea, and either increasing or decreasing appetite, depending on which plant varieties are used.  Third, this research will improve access and interpretation of genomic data, and we desire to streamline this process to make it accessible to other scientists and interested users. Fourth, the Investigation of Cannabis will increase our knowledge on the dynamics of humans and plants through the process of domestication, a process that has interested evolutionary biologists since the beginning of the field of evolutionary biology [13]. At CGRI we hope to elucidate how, through the process of domestication, humans have shaped and modified the Cannabis genome, and how this process translates into the physical traits of the plants. Finally, a better understanding of the genetic differences between wild and cultivated varieties will also be crucial for breeders, making the process of crossing divergent lineages more efficient and predictable.

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References:

1.         Thorne, R.F. Taxon, 2002.

2.         Soltis, D.E. et al. 2005: Sinauer Associates Incorporated.

3.         Lipton, L.E. Library Journal, 1997.

4.         Haston, E., et al. 2007.

5.         Hillig, K.W. and P.G. Mahlberg. American Journal of Botany, 2004.

6.         de Meijer, E.P.M., et al. Genetics, 2003.

7.         Turner, J.C., et al. American Journal of Botany, 1978.

8.         Casano, S., et al. 2011.

9.         Hillig, K.W. Biochemical Systematics and Ecology, 2004.

10.       van Bakel, H., et al. Genome Biology, 2011.

11.       Li, H.L. Economic Botany, 1974.

12.       Russo, E.B. Chemistry & Biodiversity, 2007.

13.       Darwin, C. On the origin of species., 1959.