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A new genetic study by researchers at Leiden University and Wageningen University completely refutes previous claims that a genetic mutation gave a homo sapiens an evolutionary advantage over Neanderthals to adapt to exposure to smoke from campfires.
Camber et al. to observe no significant difference between Neanderthal and modern human AHR.
“The making and use of fire is considered to be one of the most important innovations in human evolution,” said Dr. Jac Aarts, lead author of the current study, and his colleagues.
“The fire brought benefits such as heat, for example, protection from predators and a wider diet, as it made it possible to cook raw and inedible food.”
“A downside of fire is that it exposes people to the toxic substances in the smoke,” they added.
In 2016, researchers at Pennsylvania State University looked at the aryl hydrocarbon receptor (AHR) gene – which regulates the human body’s response to carcinogenic polycyclic aromatic hydrocarbons produced by fires – in modern humans and Neanderthals.
They found that modern humans carried a mutation in the AHR gene that increased their tolerance to smoke-related toxins.
They concluded that Neanderthals were up to 1,000 times more sensitive to these toxins than modern humans.
In 2018, Dr. Aarts’ team came to the opposite conclusion, based on an analysis of 19 relevant genes in existing Neanderthal, Denisovan, prehistoric and anatomically modern human genomes.
They found that Neanderthals had more genetic variants that neutralized the harmful effects of toxins better than most modern humans.
In the new study, Dr. Aarts and his co-authors repeated the previous experiences of their colleagues in Pennsylvania.
Instead of rat cells, the researchers used human cells and found that there was no reason to conclude that the AHR protein made Neanderthals more vulnerable to toxins from smoke.
“Our results are strongly in contradiction with the major role of modern human assisted reproduction in the evolution of hominin detoxification of the components of smoke and consistent with our previous study based on 18 relevant genes in addition to assisted reproduction. , which concluded that the effective detoxifying alleles are more dominant in ancient hominids, chimpanzees and gorillas than in modern humans, ”they said.
Their results were published in the journal Molecular biology and evolution.
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Jac MMJG Aarts et al. Evolution of hominin detoxification: Neanderthal and modern human Ah receptors respond similarly to TCDD. Molecular biology and evolution, published online November 24, 2020; doi: 10.1093 / molbev / msaa287
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