Humans’ relationship with marijuana is as old as agriculture in the east – 7/16/2021 – Science

The origins of marijuana (Cannabis sativa) go back to China 12,000 years ago, making the relationship between humans and plants as old as agriculture itself in the Far East.

The conclusion comes from a study by Asian and European researchers, which also suggests that cannabis was originally domesticated as a polyvalent vegetable that was used as a food and textile raw material, as well as for medicinal and recreational purposes.

The team led by Guangpeng Ren and Luca Fumagalli from the Laboratory of Conservation Biology at the University of Lausanne, Switzerland, has just published these results in an article in the journal Science Advances. The couple coordinated the sequencing (roughly “reading”) the DNA of 110 varieties of the plant from Europe, Asia and America, which enabled them to build a large “pedigree” of cannabis (see infographic).

“East Asia is considered the domestication center for many plant species such as rice, millet, peach and apricot,” Fumagalli told Folha. Everything indicates that the initial adaptation of C. sativa for humans occurred in the first wave of these domestications. This is the phase known as the Agricultural Revolution, which saw the seeds of population growth and social complexity that would characterize Chinese civilization.

The domestication of the plant took place so intensely that today there are no more close relatives of marijuana in nature. Although some varieties of the plant now grow in a wild (i.e., wild) state, their genomic analysis shows that they are domesticated forms that eventually took refuge in nature, much like the horses that populated the pampas of Rio Grande do Sul . , from Uruguay and Argentina in colonial times.

The oldest archaeological data about the plant come from its textile use, for example in the manufacture of ropes (here referred to as hemp), in China and also in Japan 7,500 years ago. However, this doesn’t necessarily suggest that the plant’s benefits were discovered first and that its psychoactive substances were not used until later, says Fumagalli.

“Based on our analysis, we conclude that about 4,000 years ago a strong divergent selection began that directed varieties towards either fiber production or drug use. This suggests that cannabis may have been a multi-purpose plant between the start of cultivation and the start of this divergent selection 8,000 years ago, ”says the researcher.

The term “divergent” used by Fumagalli to qualify the type of selection that produced the plant varieties is also explained by a biochemical peculiarity of C. sativa. What happens is that in the plant organism two enzymes (roughly speaking biochemical “scissors”) compete for the same raw material, CBGA (cannabigerolic acid).

One of these enzymes converts this raw material into THC, the main psychoactive ingredient in recreational marijuana. The other enzyme, on the other hand, leads to the production of the molecule known as CBD or cannabidiol, which is more common in hemp varieties.

When both enzymes are active, both THC and CBD are produced in modest amounts. The variety selection 4,000 years ago resulted in plants with a genetically “switched off” THC-producing enzyme on the one hand and plants with a deactivated CBD enzyme on the other.

By the way, this conclusion is an important element for the future improvement of the plant for various uses, especially medicinal purposes. Based on a detailed understanding of how the genes that hold the “recipe” for making these enzymes work, it should be possible to create strains of C. sativa with the desired combination of molecules in your body.

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