Cannabis in the Stone Age, the origins of breeding
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Studies on the origins of cannabis are becoming more frequent as global interest in this plant has skyrocketed in recent decades. Whether we talk about the place of origin, the date of domestication or the oldest dated samples found, our curiosity about human's relationship with this ancient plant grows every day, thanks in part to the process of legalisation and normalisation that we see taking place in many countries.
In this article, we want to go back to the beginning of this relationship, and to do this, we need to take you on a journey through time, back to the Stone Age, when humans established their first settlements and started a key activity for their development: agriculture. And, naturally, you can already guess what one of the first plants cultivated by mankind was... Cannabis, of course!
Stone Age, the birth of agriculture
The Stone Age is a broad period of History - in fact, it is considered the first period of prehistory - that includes a vast space of time, approximately from 3 million years ago (the first tools) until the year 4,000 BC, when metals were discovered and the Copper Age began. During this long period, the first stone tools were made and activities such as agriculture, crafts or the preparation of foods such as bread and cheese began.
In turn, this period is usually divided into three others, Paleolithic, Mesolithic and Neolithic; and it is the latter two that we are going to focus on here, from approximately 12,000 BC until the discovery of metals. It was during these two periods that humanity became sedentary, settling down in certain areas and prospering thanks to hunting, plant cultivation, and the manufacture of tools and supplies such as baskets, fabrics and ceramics. We can therefore speak of these being real settlements within the first agrarian societies in our history.
The earliest samples of cannabis found
If we talk about the earliest physical evidence of the use of cannabis, the hemp rope sample obtained from a site in China is probably the oldest, with a date that points to approximately 12,000 BC. We emphasise that this is the earliest evidence of its use, not the earliest sample of cannabis obtained, which would be pollen grains dating from roughly 19.6 million years ago. Based on studies on pollen grains identified as belonging to cannabis, a group of researchers propose an area of the Tibetan Plateau as the place of origin of cannabis, in the vicinity of Lake Qinghai.
The research points to the idea that cannabis remained isolated in the highlands of Asia for millions of years, before spreading to other territories and beginning to be cultivated for its many applications, from making ropes to obtaining seeds as food and, of course, also for its psychoactive properties.
Signs of cannabis domestication
Although there is debate among leading researchers as to how cannabis spread and was domesticated as far afield as East Asia and Europe, it seems clear that the origins of the plant are Eurasian. However, this leaves us with an extremely wide geographical area, so efforts to narrow down the area where the plant originated continue unabated. Until recently, it seemed clear that cannabis had originated somewhere in Central Asia and from there the predecessor tribes of European cultures would have domesticated it and dispersed it to the East.
However, the latest studies point to the idea that cannabis would have been domesticated in Asia around 11,000 BC, but also, and almost simultaneously, in other territories such as Japan or Eastern Europe. According to these investigations, the use of cannabis would be much more common in areas of East Asia than in Central Asia or Eastern Europe, although the evidence found in the studied sites seems to demonstrate that this domestication took place in several areas and almost simultaneously (between 11,500 BC and 10,200 BC). It would not be until practically the Bronze Age that its use would have intensified in other areas of Asia, perhaps taking advantage of the first beginnings of the future Silk Road, and it seems, thanks in part to its psychoactive properties.
However, remains of seeds have been found in European Neolithic sites as far away from East Asia as Italy, Romania and even Spain, which would indicate that at some point in this period there would indeed have been a westward expansion of the plant, largely into part of the territory that we now call Europe or, alternatively, it could show that there was already indigenous cannabis in Europe at that time. Some investigations point to the Hexi Corridor as the geographical passage through which this expansion towards European lands would have occurred during the Neolithic, while others suggest that this expansion would have occurred somewhat later, at the beginning of the Bronze Age. The debate is still open.
The first breeders: cultivation and selection of cannabis in the Stone Age
That the cannabis varieties we know today come from centuries of selection for certain traits by humans is something that we can clearly appreciate today. However, when did this selection process begin? When did cannabis start to be bred for fibre or psychoactive purposes? Well, according to a 2021 study published in Science Advances, this process would have begun at the beginning of the Neolithic period in the area where we have already seen that its use was most intensive, East Asia.
According to the researchers, cannabis would have been domesticated at this time from the landrace varieties of China. In addition, the genes responsible for the production of fibre (hemp) and psychoactive plants were compared, observing that it was during this period when both types of plants began to clearly differentiate, which indicates a process of trait selection by the growers. Thus, these first Neolithic cannabis growers would have been responsible for separating both types of plants and crossing them among themselves to strengthen the desired characteristics in future offspring.
Undoubtedly, these investigations would be much simpler if the wild ancestor of cannabis was available today, but unfortunately, it is long extinct. Because of this, the studies must be carried out with the varieties that we currently have (hemp, psychoactive varieties and landraces), which complicates things quite a bit. What does seem clear is that, at a genetic level, landrace varieties from China are the most similar to this extinct ancestor, which points to this area as a possible origin of domesticated cannabis and, therefore, of the varieties we know today. today.
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Conclusions on the domestication of cannabis
We see that as more and more studies on the origins of cannabis and its domestication come to light, both the time period and the geographic area where these phenomena occurred are narrowed down. Even so, and as often happens, some studies seem to contradict each other, pointing to different areas or proposing different theories about their domestication and expansion.
As we have seen, there is still debate today between Central Asia and East Asia as the "cradles" of cannabis, as well as the way in which the plant spread to distant territories. In addition, the latest research on the first samples of cannabis in Europe deserves careful study, as it could turn many theories upside down.
Undoubtedly, as scientific research advances, we will have more data and it will be easier to draw conclusions, although always bearing in mind that... archaeology is not like mathematics!
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Sources:
- Cannabis in Eurasia: origin of human use and Bronze Age trans-continental connections, Tengwen Long, Mayke Wagner, Dieter Demske, Christian Leipe, Pavel E. Tarasov
- Large-scale whole-genome resequencing unravels the domestication history of Cannabis sativa, Guangpeng Ren, Xu Zhang, Ying Li, Kate Ridout, Martha L Serrano-Serrano, Yongzhi Yang, Ai Liu, Gudasalamani Ravikanth, Muhammad Ali Nawaz, Abdul Samad Mumtaz, Nicolas Salamin, Luca Fumagalli
- An Archaeological and Historical Account of Cannabis in China, Hui-Lin Li
- Cannabis utilization and diffusion patterns in prehistoric Europe: a critical analysis of archaeological evidence, John McPartland, William Hegman
- Cannabis is indigenous to Europe and cultivation began during the Copper or Bronze age: a probabilistic synthesis of fossil pollen studies, John McPartland, Geoffrey W Guy, William Hegman
- Origin, early expansion, domestication and anthropogenic diffusion of Cannabis, with emphasis on Europe and the Iberian Peninsula, Valentí Rull