Archaeobotanical studies of cannabis pollen suggest that his plan may have originated and began to be cultivated first in the Tibetan plateau, sometime in the distant past.
Cannabis is probably one of the best-known plants on Earth because it produces cannabinoids, chemicals that have a pronounced impact on the human brain.
Previous studies have suggested that the plant probably originated somewhere in Central Asia about 28 million years ago, the point at which it separated from an ancestor, the common leap.
But a new study has changed what we thought we knew about this plant.
Researchers from the University of Vermont, Middlebury College and the University of Nottingham tried to pinpoint more precisely where the plant originated from.
They publish their results in the magazine Vegetation History and Archaeobotany, suggesting the plant’s origins can be traced back to the Tibetan plateau.
Titled, “Cannabis in Asia: its center of origin and early cultivation, based on a synthesis of subfossil pollen and archaeobotanical studies”, the scientists wanted to establish the oldest common ancestors of the cannabis plant.
Tracing its origin
The approach used by the researchers was to analyze previous studies, whether archaeological or geological, searching for traces of the famous plant; most notations refer to pollen because it is the part of the plant that can survive the most.
Experts have pointed out that identifying cannabis pollen at excavation sites was not a trivial task, because, in most tests, it appears to be identical to hop pollen.
To solve this problem, they took note of other types of pollen that were found with cannabis candidates.
If the other pollen came from forest plants, the researchers assumed that they were hops, whereas if they came from steppes, the pollen was assumed to come from a cannabis plant: modern cannabis plants prefer the type of climate found in steppes.
When the researchers focused on the studies that mentioned cannabis (found with other steppe pollen), they found references to parts of southern Russia and northern China.
However, a more profound analysis led them to believe that the most likely place of origin was the Tibetan plateau, perhaps near Qinghai Lake, which is approximately 3,200 meters above sea level.
“Cannabis and Humulus diverged 27.8 Ma, estimated by a molecular clock analysis. We bridged the temporal gap between the divergence date and the oldest pollen by mapping the earliest appearance of Artemisia,” wrote researchers in their study.
“These data converge on the northeastern Tibetan Plateau, which we deduce as the Cannabis center of origin, in the general vicinity of Qinghai Lake. This co-localizes with the first steppe community that evolved in Asia. From there, Cannabis first dispersed west (Europe by 6 Ma) then east (eastern China by 1.2 Ma). Cannabis pollen in India appeared by 32.6 thousand years (ka) ago. The earliest archaeological evidence was found in Japan, 10,000 bce, followed by China,” revealed scientists.
Interestingly, researchers also note that the site where cannabis may have originated from is not far away from where experts discovered evidence of Denisovan populations, as well as cannabis pollen.