The history of cannabis is long and complex. In fact, it can be difficult for scientists to study the plant given the multitude of laws banning or limiting cannabis worldwide. But the once anti-cannabis mentality is changing on a grand, multinational scale. As such, new research into the origins of cannabis plants is changing how we approach its history.
The American Association for the Advancement of Science (AAAS) published a study in June detailing the roots of ancient cannabis like never before. Researchers used genomic, evolutionary, and demographic analyses to study 110 diverse species of cannabis. Their methods yield new understandings, including when humans first cultivated cannabis, and how hemp and marijuana—cousin plants within the Cannabis sativa L. plant family—diverged, favoring different genetic traits.
But the results of this study reach far beyond the scope of cannabis or even cannabis history. In fact, the conclusions from this study offer credibility to other areas, including the science of human history, agriculture, and more.
We’ll take you through this June study step-by-step so that you can see the full implications and conclusions offered by this riveting research. Let’s get started!
According to the study: “All our analyses show a strong clustering of Cannabis accessions into four well-separated genetic groups.” Think of an accession like a ranking used to differentiate the four main types of cannabis.
And what are these four cannabis accessions, according to the study?
- Basal Cannabis (Group A)
- Hemp-Type Cannabis (Group B)
- Wild Drug-Type Cannabis (Group C)
- Cultivated Drug-Type Cannabis (Group D)
NOTE: the study often refers to marijuana as “drug-type” cannabis. This is to signify that these cannabis groups are often used for their psychoactive properties.
According to the results of the study and accompanying analysis, the basal (“base”) group is an ancient cannabis ancestor to other cannabis accessions. Both hemp and drug-type cannabis strains genetically diverged from the basal group in roughly 12,000 B.C.E. This indicates that the basal species of ancient cannabis had already been domesticated by early Neolithic times.
The Geographic Origins of Cultivated Cannabis
Because of basal’s geographic origins, the study concluded that the cultivated cannabis plant (as we know it today) began in East Asia, contradicting past accepted understandings. Please note that the study uses the terms landrace (a local plant improved by traditional agricultural methods) and cultivar (a plant produced in cultivation by selective breeding) to describe different cannabis genomes.
“Contrary to a widely accepted view, which associates Cannabis with a Central Asian center of crop domestication, our results are consistent with a single domestication of origin of C. sativa in East Asia, in line with early archaeological evidence. The results also indicate that some of the current Chinese landraces and wild plants represent the closest descendants of the ancestral gene pool from which hemp and marijuana landraces and cultivars have since derived.”
- Cannabis was first cultivated in East Asia, not Central Asia.
- Archaeological evidence already suggests first cultivation in East Asia, corroborating the study’s conclusions.
- Modern cannabis strains in China (both wild and cultivated varieties) are the closest descendants of ancient cannabis we have today. This includes both hemp and marijuana strains.
And remember when we said that this study has implications for the science of human history as well? The study notes that “East Asia has been shown to be an important ancient hot spot of domestication for several crop species, including rice, broomcorn, and foxtail millet, soybean, foxnut, apricot, and peach; our results thus add another line of evidence for the importance of this domestication.”
The Evolutionary Topology of Cannabis
While the AAAS study marks a prominent step forward in the quest to understand cannabis’ complete ancestral history, we still do not have enough information to form a complete (geographic) cannabis family tree. However, the AAAS’s study offered some promising new information:
- Modern hemp strains (Group B) derive from China as well.
- There is substantial differentiation between wild drug-type plants (Group C) and modern European and American cultivars (Group D). The difference comes from “intense recent selection for high THC content.”
- There are similar levels of genetic diversity between basal cannabis (Group A) and the other groups.
At first glance, the last point listed isn’t particularly earth-shattering. However, it does carry some groundbreaking implications. According to the study:
“Although additional sampling of feral plants in these key geographical areas is still needed, our results, which are based on very broad sampling already, would suggest that pure wild progenitors of Cannabis sativa have gone extinct.”
In short: Wild cannabis has become extinct. Yes, there still exist wild cannabis plants growing today, but these modern feral varieties are not truly wild-type cannabis. Instead, they are “historical escapes from domesticated forms,” meaning cultivars or landraces that took wild roots outside of farms or production areas.
Furthermore, the study proposes that selective breeding of Cannabis sativa took off at a titular point, around 4,000 B.C.E. At this point in the history of cannabis, it is proposed that farmers began choosing cannabis traits for either increased fiber production (Group B) or increased psychoactive properties (Group C, Group D). This selectivity, over the course of thousands of years, is likely why we see so many diverse strains of hemp-type and drug-type cannabis today.
Ancient Cannabis, in Conclusion
As you can see, the AAAS study opened many doors for the history of cannabis. Let’s review what we’ve learned so far:
- Researchers compiled genomic, evolutionary, and demographic analyses of 110 Cannabis sativa strains; these analyses will continue to serve the scientific community for ongoing research into molecular breeding and research into both medicine and agriculture.
- There are four primary cannabis accessions (basal, hemp-type, wild drug-type, and cultivated drug-type).
- Hemp and drug-type cannabis strains diverged from basal cannabis in about 12,000 B.C.E.; major differentiation came around 4,000 B.C.E, when farmers began selectively breeding for fiber production or psychoactive properties.
- Cannabis was first cultivated around 12,000 B.C.E. in East Asia, not Central Asia.
- Modern cannabis strains found in China most closely resemble ancient cannabis strains found in the basal accession (Group A); modern hemp strains (Group B) also derived from China.
- Truly wild cannabis has likely become extinct; the wild cannabis we see today are escaped domesticated forms of cannabis.
We mentioned earlier that studying the history of cannabis can be difficult. There are laws worldwide that limit cannabis in all ways imaginable. However, scientists are beginning to pass through barriers, especially as the plant’s acceptance climbs to an all-time high. And as more areas legalize cannabis, more research opportunities will unveil themselves.
The AAAS study proves that, with time, we’ll learn fascinating information about both the cannabis plant and how it plays a role in our own human history. Who knows: as one of the first cultivated plants in existence, maybe cannabis plays a larger role than we’ve been led to believe?