The cannabis plant originated in China and was domesticated in the Stone Age, according to the latest studies
Thanks to a long history of domestication, the cannabis plant now comes in a variety of different cultivars, each cultivar with its own unique composition of cannabinoids and other compounds. According to new research in the journal Science Advances, this process of selective breeding may have begun during the early Neolithic period in what is now northwest China, where wild cannabis first appeared.
Previous genetic studies have suggested that cannabis originated in the Tibetan plateau, although the oldest archaeological evidence for hemp rope use comes from China, dating back nearly 12,000 years according to the authors of this study. As such, it is widely agreed that the plant probably had its roots somewhere in Asia, however determining where it originated has proven challenging.
This is largely due to the fact that the wild ancestor of cannabis is now extinct and thus cannot be studied directly. In their place are a number of specially cultivated strains of both cannabis and cannabis, as well as some ancient cultivars called botanicals. While these species are not the same as the original cannabis plants, they are less domesticated than modern commercial strains, having been altered over the centuries by natural selection rather than extensive human-led breeding programmes.
To trace the history of this plant, the study authors analyzed the genomes of 110 cannabis plant species from around the world and found 82 new and 28 known genomes. These include the full range of modern and original strains as well as wild cultivars that They grow when the seeds are “escaped” from domesticated varieties and allowed to grow and reproduce naturally.
After evaluating the genetic relationships between all of these plants, the researchers noted that every modern strain of cannabis and cannabis can be traced back to an "ancestral gene pool" that appears to have its roots in Chinese strains and wild plants.
“The present Chinese strains and wild plants represent the closest descendants of the ancestral gene pool from which hemp and marijuana strains and cultivars have since evolved,” the study authors wrote.
“Contrary to the widely accepted view, which links hemp to crop domestication in Central Asia, our results are consistent with a single origin for the domestication of cannabis in East Asia.”
Furthermore, genomic history revealed that the first domesticated ancestors of modern cannabis plants diverged from this wild ancestor around 12,000 years ago, “suggesting that this species was already domesticated in the early Neolithic period.”
Since then, the massive breeding of this plant by humans has led to the emergence of several distinct genetic groups, with cannabis and cannabis being two of its species. When comparing these two cultivars, the study authors found 134 genes specific to cannabis and 472 genes unique to psychoactive cannabis.
These genes control plant traits such as branching and flower formation, as well as potency. For example, the genes that code for an enzyme that synthesizes tetrahydrocannabinol (THC) - the main psychoactive component in cannabis - are fully expressed in most drug-type plants but are lacking in cannabis.
Source: IFLScience website