For many years, many experts agreed that the cannabis plant originated in Russia and Kazakhstan, perhaps India, while others relied on evidence that the source was Taiwan Island, which lies east of China.
Researchers at the University of Vermont now offer a new theory, based on a comprehensive study of ancient fossil powders, according to which the genetic origin of the cannabis plant is at an altitude of 3,260 above sea level in China, just between Kazakhstan, India and Taiwan.
More precisely, according to the study, the plant originated from 19.6 a million years ago in the area of Qinghai Lake, located in the Tibetan Plateau in the southern Qinghai province in the center of China, north of Tibet, Nepal and the Himalayas.
"Despite extensive literature over the last three decades, the definition of cannabis has remained controversial," the scientists wrote in the study Published Last week in the Journal of Vegetarian History and Archeobotany.
Since there are not enough Cannabis leaf fossils, the researchers have decided to review fossil plant powders collected since the 30 of the last century and have been identified as related to the genetic family of Cannabis.
The researchers reviewed 155 studies of such fossilized powders originating in Asia, with the challenge being to distinguish between cannabis genetics and that of plants from hops genetics - a cannabis 'cousin' from which beer is produced.
To distinguish between the two plants, which they estimated to have separated from each other about 28 a million years ago, the researchers used statistical models to compare cannabis and hops with other plants from similar genetic families.
"Although this is a hypothesis that will probably be impossible to prove, according to the evidence we have, the results show that the most likely geographical area to be the source of cannabis is Lake Kingai," they determined.
From this region researchers believe cannabis began spreading westward, through Russia, to Europe's before 6 million years ago, and east to east China before 1.2 million years - and from there to all over the world.
It is estimated that humans use cannabis for recreational and medical purposes for about 2,700 for years and for industrial purposes for about 7,000 years.