For countless generations, the use of cannabis has been deeply woven into the tapestry of human civilization. From its ritualistic roles in ancient cultures to its present-day presence in medical and recreational settings, marijuana has long been a source of fascination—and controversy.
Despite its widespread use and cultural significance, the true origins of cannabis have remained elusive for centuries. Political restrictions, legal taboos, and the clandestine nature of cultivation have all contributed to an incomplete scientific understanding of the plant’s ancestry. But now, a significant breakthrough has been made.
A team of researchers has uncovered new genetic insights that shed light on where Cannabis sativa— the species that includes both marijuana and hemp—first appeared and how it diverged into the varieties recognized today. This groundbreaking discovery, detailed in the journal Science Advances, offers a new perspective on the evolutionary history of one of the most debated plants in human history.
A Genomic Exploration Into the Past
Through advanced genetic research, scientists examined 110 distinct cannabis genomes from around the world. With the aid of next-generation DNA sequencing technologies, a clearer picture has emerged of how Cannabis sativa evolved and diversified. It was through this comprehensive molecular investigation that a long-missing chapter of the plant’s evolutionary history was brought to light.
By analyzing the DNA sequences, researchers were able to construct phylogenetic trees—essentially genetic family trees—that outline the relationships among different cannabis lineages. What these genetic maps revealed was a structured evolution into four genetically distinct cannabis groups. Most notably, they identified a foundational group known as “basal cannabis,” which had previously escaped detection in earlier research efforts.
The Discovery of Basal Cannabis
Among the most remarkable findings of the study was the identification of this basal cannabis group. It has been described as a sister group to all other cannabis varieties, meaning it stands genetically apart from modern cultivated hemp and psychoactive marijuana. This group includes feral strains and landrace varieties—local, traditionally bred strains—still found in parts of China today.
This group’s genetic distinctiveness suggests that it may hold the closest resemblance to ancient, wild cannabis plants that existed before human intervention began to shape the species through selective breeding.
According to Dr. Luca Fumagalli, a conservation biologist from the University of Lausanne and one of the study’s co-authors, cannabis ranks among the earliest plants cultivated by humans. Yet, despite its long history of cultivation, its scientific documentation has lagged behind due to persistent socio-political complications. “Few crops have been as steeped in controversy as Cannabis sativa,” he noted.
A Closer Look at Cannabis Diversity
The study categorized cannabis into four main genetic groups, each offering a glimpse into a different aspect of its evolutionary journey:
- Basal Cannabis: This ancestral group includes wild and landrace cannabis varieties, primarily located in China, which share genetic markers unseen in modern cultivated strains. Its presence suggests the earliest domesticated cannabis likely emerged from East Asia.
- Hemp: This group consists of non-psychoactive cannabis varieties grown primarily for their fibers, seeds, and oils. Hemp has historically played a significant role in textiles and industry, particularly in Europe and North America. Its low concentration of THC—the compound responsible for the plant’s psychoactive effects—distinguishes it from drug-type cannabis.
- First Drug-Type Cannabis Group: This group comprises both wild and cultivated psychoactive cannabis varieties primarily originating in South and Central Asia, including present-day China, India, and Pakistan.
- Second Drug-Type Cannabis Group: This category includes drug cannabis strains cultivated globally, particularly in regions where marijuana use is culturally or medically widespread.
Through genetic comparisons, it became evident that cultivated cannabis had its origins in East Asia, overturning earlier assumptions that placed its beginnings in Central Asia. Furthermore, it was determined that the divergence between basal and cultivated cannabis occurred nearly 12,000 years ago—coinciding with the dawn of agriculture itself during the early Neolithic period.
Domestication: A Double-Edged Sword
The separation of cannabis into fiber-producing hemp and psychoactive marijuana appears to have taken place around 4,000 years ago. This period aligns with archaeological records showing the emergence of hemp-based fiber artifacts in East Asia during the Bronze Age. From there, the cultivation of cannabis spread westward, reaching Europe and eventually other parts of the world.
Interestingly, it has been proposed that cannabis was not initially cultivated with a singular purpose. For millennia, it likely served as a multi-functional crop—used for fiber, food, medicine, and even spiritual or recreational activities. It wasn’t until later that distinct traits were selectively bred to create highly specialized hemp and marijuana varieties.
As human cultivation intensified, so too did the plant’s genetic transformation. Certain genes associated with cannabinoid production and fiber strength underwent mutations or were selectively lost, depending on the desired traits. The result was an irreversible split between hemp, valued for its durability and utility, and marijuana, prized for its psychoactive and therapeutic properties.
This long-term genetic tampering appears to have come at a cost. Researchers believe that the original wild ancestors of Cannabis sativa may now be extinct, having been completely replaced or assimilated into cultivated strains. In essence, the species was genetically re-engineered by humanity over thousands of years.
A Global Journey
The spread of cannabis was not a uniform process. According to the research, psychoactive strains moved from East Asia to India roughly 3,000 years ago. From there, they gradually expanded to Africa and Latin America within the past millennium. North America’s encounter with the plant, however, came much later.
Hemp was introduced to colonial North America in the 1600s by European settlers, where it was initially grown for rope and textiles. However, by the mid-19th century, Chinese cannabis varieties began to replace the older European hemp strains. It wasn’t until the early 20th century that marijuana—with its psychoactive potency—began making a noticeable appearance in North American society.
This global dissemination of cannabis has further diversified its gene pool, leading to an array of strains that vary not just in appearance and potency but also in their biochemical makeup.
Rethinking Cannabis Classifications
One of the more compelling implications of this study lies in the current legal and scientific definitions of cannabis. Traditionally, cannabis plants have been divided into two categories: hemp and marijuana. However, the genetic findings suggest that this binary distinction may be more of a social construct than a scientific one.
Within the DNA of the samples studied, notable differences were observed in the genes responsible for the synthesis of THC and CBD—two of the most prominent cannabinoids. While THC is known for its mind-altering effects, CBD is sought for its potential therapeutic benefits without psychoactive impact.
Interestingly, five hemp samples exhibited unexpected genetic complexity, blurring the lines between what is legally defined as hemp versus marijuana. This ambiguity raises important questions about how cannabis should be classified and regulated moving forward.
As noted in the study: “From both a biological and functional perspective, the current binary categorization of cannabis as either ‘hemp’ or ‘marijuana’ is brought into question.”
