It's probably not controversial to say that the discovery of fire improved the lives of early humans. But there were probably some harmful effects too, says The New York Times. Smoke could have burned their lungs, and char-coated food could have upped their chances for certain cancers.
Fire shaped human evolution, and now researchers say even the negative effects may have contributed to how man evolved.
For example, says the Times, one new study has identified a genetic mutation that allows modern humans to safely metabolize certain toxins, including some found in smoke. So far, that genetic mutation has not been found in the DNA of other primates or ancient hominins such as Neanderthals and Denisovans.
"The researchers believe the mutation arose in response to breathing in smoke toxins, which can increase the risk of respiratory infections, suppress the immune system and disrupt the reproductive system," the Times says. It's even possible that the mutation gave modern humans a leg up on Neanderthals.
Other research has suggested that the microbiomes of modern humans evolved to take advantage of the byproducts fire leaves in food, the article says.
Fire may have also contributed to the spread of certain diseases. A second study published recently says early use of fire may have spread tuberculosis as smoke caused large groups of people gathered around the fires to cough and spread the infectious disease further than before.
And, of course, inhaling smoke may have led to man's discovery of smoking, the Times says.