Humans evolved to survive mild burns at the expense of severe ones

Early humans had almost no hope of surviving severe burns, so evolution may have prioritised the selection of genes that heal mild ones, which could be affecting modern medicine

By Christa Lesté-Lasserre

28 April 2025

Hominins have been using fire for various reasons for at least 1 million years

SHEILA TERRY/SCIENCE PHOTO LIBRARY

Mastering fire may have also led to genetic changes that helped early humans survive mild burn injuries, but this evolutionary trait could complicate the treatment of more severe cases today.

An early-stage study suggests that the selection of genes preventing deadly infections that could arise from minor burns were prioritised in early Homo sapiens, but these same genes interfere with the healing of severe ones. This may be because, in primitive times, people with severe burns had almost no hope of surviving.

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For at least 1 million years, hominins have been using fire – whether for cooking, warmth, protection or tool manufacture – and so putting themselves at risk of burns. Scientists have already found that Homo sapiens may have evolved to overcome some kinds of smoke toxicity.

Joshua Cuddihy at Chelsea and Westminster Hospital NHS Foundation Trust in London and his colleagues suspected that fire-related skin injuries might have shaped human evolution too. To find out, they analysed previously published data on the genes expressed in burnt and healthy skin of rats and humans, identifying 94 that were only expressed during burn healing.

They then ran further analyses on published genetic data from humans and chimpanzees, our closest living relatives. The team looked for signs of enhanced natural selection for these 94 genes in humans compared with chimpanzees, pinpointing 10 burn-healing genes that underwent significantly stronger selection in people.