Humans have been using cannabis for millennia, but scientists still do not know much about the devil's lettuce. With new research, we now have a potential answer to a persistent mystery of pot science: why does the weed contain the special chemical compounds that affect humans, unlike other plants?
Of course I am talking about THC and CBD, compounds called cannabinoids that are found in cannabis and have various effects on humans. THC is well known as the main psychoactive component of cannabis (that is, it excites you), and CBD has recently become a fashionable ingredient as an ingredient of everything from drinks to cosmetic products.
According to a study published in the November issue of Genome researchthese two distinct compounds did not always exist in the plant we now call cannabis. According to the study, millions of years ago, old viruses could have colonized the genome of the plant and accelerated an evolutionary process that altered its DNA and gave us THC and CBD.
"The proteins [for THC and CBD] are embedded in this huge mess of virus-like sequences, "said Tim Hughes, professor of molecular genetics at the University of Toronto and co-authored the study, by phone. "These sequences are known to facilitate rearrangement of the chromosome, and they are actually a bit dangerous in this way."
According to Hughes, these viruses could have accelerated an evolutionary process that would have resulted in the mutation of an enzyme gene in the cannabis in half, which would ultimately give us THC and CBD. "It's easy to imagine that over a long period of time this process has been repeated time and again in this part of the chromosome where these two enzymes are found," he said.
According to a press release published as part of this study, this change has led to a split of old cannabis into chemically distinct types. Humans were then selected for plants with the desired characteristics, such as high THC levels.
It's hard to tell what cannabis looked like before the old viruses helped her develop the properties we're familiar with today, but according to Hughes, some of her closest relatives are harmless plants like the mulberry and the hop.
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The discovery that ancient viruses are probably the reason people turn on cannabis to break down is a byproduct of Hughes and colleagues' research, which is the first complete map of the cannabis genome to be published academically. . In February, Colorado-based start-up, Sunrise Genetics, unveiled a cannabis genome map at a conference but did not publish an article, claiming that it would share work publicly "in less than a year". Hughes and his colleagues have published a cannabis project. genome in 2011, but it was not detailed enough to reveal the position of genes on the chromosome.
Such cards are essential to improve our impoverished understanding of the cannabis plant. Hughes and his colleagues already do more than discover the possible role of viruses in the production of THC and CBD. According to the researchers, they also identified a gene responsible for the production of a third cannabinoid called CBC.
And there is still much to learn about a plant that many people consume regularly, but science has not yet understood. According to Hughes, one of the most important is the use of THC and CBD for the cannabis plant itself, assuming that these compounds developed well before humans roamed the Earth. "It's just casual that they have these effects on people," said Hughes.
We could soon see further studies deepening the fundamental unknowns of cannabis science through a new wave of research following the legalization of the plant in Canada. Previously, it was difficult for researchers to get their hands on the plant to study and the money needed to conduct their research. Now this is changing and our understanding of cannabis too.
"It's a plant and it does these biochemical things, and it's not like we do not have the ability to do everything we can with other plants, animals, and microbes," Hughes said. . "It's just that nobody does it because we can not do it."
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