The question of how and why psychedelic mushrooms evolved to contain their active ingredient psilocybin has long intrigued scientists. Now, a groundbreaking study led by evolutionary fungal genomicist Jason Slot from Ohio State University promises to shed light on this puzzle, and open up the door for more research on the topic.
The study investigated the effect of magic mushrooms on the brains of flies. It was found that psilocybin acts by suppressing a particular neurotransmitter – causing hallucinations in humans, but suppresses appetite in flies. This suggests that although psilocybin is not toxic, it evolved as a survival strategy to prevent the mushrooms from being eaten.This makes sense, since the majority of magic mushroom species grow in insect-rich environments, but still leaves a puzzling question open. Why is psilocybin found in almost 200 different species of mushroom, spanning more than one genus? The likelihood of the exact same compound evolving independently numerous times is incredibly low, indicating a different mechanism being responsible for this.
The researchers at Ohio State University found horizontal gene transfer to be the answer. Horizontal gene transfer is a blanket term for several mechanisms through which one organism passes its genetic material to another organism which is not its offspring, meaning that genes can be passed between different species in some cases. As odd as it sounds, horizontal gene transfer occurs surprisingly often in nature, and can occur through the help of viruses. In the case of magic mushrooms, it explains why numerous distantly related species ended up with the same non-toxic, appetite reducing defense against predation.
Human fascination with psilocybin runs deep, and there is evidence to suggest that it has been used for ritualistic practices for thousands of years. A better understanding of how and why it evolved, as well as its mechanisms of action can help researchers develop and improve on numerous therapies based on magic mushrooms – some of which have shown great potential in treating conditions such as depression and PTSD.
It is truly astounding that a substance found in nature can produce such vivid hallucinations, and mind-altering experiences in humans. Terence McKenna’s famous ‘stoned-ape’ theory even suggests that the evolution of human consciousness was aided by the consumption of magic mushrooms; a theory which may lack evidence, but whose popularity is a testimony to the fascination us human beings have with mind-altering substances.