New research suggests that more than a million years of human use of fire have exerted evolutionary pressure that has shaped our healing, inflammation, and immune mechanisms. The benefit: better recovery from minor burns. The possible cost: higher vulnerability to complications from straw burns
For more than a million years, fire has been one of the most important technologies in human history. It has enabled cooking, heating, protection, processing materials, and, later, the development of more complex cultures. But alongside all these obvious benefits, fire has also brought with it a constant danger: burns. Now, new research suggests that this danger was not just a side effect of human progress, but also an active evolutionary force, gradually shaping our biology.
The paper, published in the journal BioEssays, was written by researchers from Imperial College London, Chelsea and Westminster Hospital and Queen Mary University of London. Their central argument is that burns are largely a uniquely human injury. Other animals are generally wary of fire, and do not live near it on a regular basis. Humans, on the other hand, have made fire an integral part of their lives. So while burns are a rare occurrence in most species, minor burns are relatively common in humans, and were probably the same for our ancient ancestors.
According to the researchers, this situation created natural selection pressure over many generations. Those whose bodies were better able to cope with small, frequent burns—that is, to prevent infection, close the wound more quickly, and respond quickly to damage—gained a survival advantage. In an ancient world, where there were no antibiotics, advanced dressings, or burn departments, any skin injury could quickly turn into a life-threatening infection. Therefore, even a relatively small improvement in healing ability could affect survival chances.
The researchers suggest several possible mechanisms that were selected during evolution: a faster inflammatory response, faster wound closure, and increased pain sensitivity, which reduces the chance of further exposure to heat. These are traits that may be very useful when it comes to minor burns. But here comes the important twist of the study: those same mechanisms may become a double-edged sword when the burn is severe and extensive. In such a case, an overly strong inflammatory response may lead to increased scarring, systemic damage, and even organ failure. In other words, evolution may have equipped us with effective mechanisms to deal with minor burns, but not necessarily with serious injuries.
To test the idea, the researchers compared genomic data from humans and other primates. They found several genes related to burn response, tissue healing, inflammation, and immune defense that appeared to have evolved more rapidly in humans. These findings do not provide conclusive proof that fire alone shaped these genes, but they do support the hypothesis that repeated exposure to burns was a significant factor in the human environment and could therefore have influenced our evolutionary trajectory.
Dr. Joshua Kadihi, the lead author of the study, defines burns as a "uniquely human injury." According to him, no other species lives alongside high temperatures and at constant risk of burns as humans do. He mentions that the connection to fire is deeply embedded in human culture, from a preference for hot food and boiled liquids to technologies that depend on heat. In his opinion, most humans are burned repeatedly during their lives, and this pattern probably reflects a very ancient pattern that has accompanied humanity since the beginning of the control of fire.
Culturally derived selection pressure
Professor Armand Leroux, an evolutionary biologist at Imperial College, highlights the broader aspect of the study: this is a possible example of selection pressure originating from culture. That is, humans created a new environment for themselves through the regular use of fire, and this environment in turn began to shape their biology. This is a particularly interesting idea because it extends evolutionary thinking beyond classic natural factors such as climate, predators or disease, and shows how cultural innovations can also become biological selection forces over time.
The study also has potential medical implications. If humans do have unique adaptations to burn injury, it may explain why animal models don't always provide a complete picture of what happens in human patients. The researchers believe that a better understanding of the evolutionary background to the body's response to burns could help develop better treatments in the future, as well as why different people recover differently from the same injury.
Of course, it should be emphasized that this is a hypothetical interpretation at this point, even if it is based on genetic analysis and compelling evolutionary logic. The study does not prove unequivocally that burns were the central factor that shaped human healing mechanisms, but it opens up an original and thought-provoking angle on the place of fire in the human story. Fire may not only have cooked our food, warmed our bodies, and lit our nights, but also slowly and gradually burned its mark into our genome.
for the scientific article DOI: 10.1002/bies.70109
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One response
Most mammals and all other primates also have fur that protects their skin from various injuries, which perhaps reduces the need for the responses attributed here to fire handling.