Convergent Adaptation of Noses in Neanderthals and Modern Humans

An international team of researchers has found that Neanderthals and modern humans both evolved in ways that allowed for better breathing through the nose in a cold climate. In their paper published in Proceedings of the National Academy of Sciences, the group also notes that there were similarities in the ways that both adapted to the cold.

In order to breathe through the nose when it is really cold outside, the air that is inhaled must be both warmed and humidified to prevent damaging sensitive lung tissue. We humans have evolved to allow this. And as it turns out, Neanderthals did, too. But, it took some roundabout research to make this discovery because much of the internal nasal configuration is made of soft tissue, which does not appear in the fossil record. To overcome that problem and to learn more about the ways both groups evolved to deal with the cold Eurasian climate, the researchers studied the nasal cavities of 38 modern Argentinians, 26 Southwestern Europeans, 12 Northeastern Asians and two Neanderthal. The team then used data from the modern humans and software to digitally reconstruct the soft nasal tissue inside the Neanderthal nasal cavity and compared it to the modern human nose.

The researchers report that though the two groups had different nose shapes (Neanderthal noses were shorter and broader than modern human noses) there were internal similarities between them that their research showed evolved independently. They also compared air warming and humidifying efficiencies between the groups. They report that they found Northeastern Asians were the best at breathing in cold air and that the Neanderthal came in second. Those of Southwestern European descent were the worst.

Both groups also evolved other adaptions to deal with the cold, such as growing more hair and becoming wider in the thoracic area. Some have suggested that the Neanderthal may have adapted too well to the cold and that might have been part of the reason the group went extinct—they could not handle the warmer temperatures that came later. This new research suggests if that was the case, it was not likely due to an inability to breathe warmer air.

Read more at: https://phys.org/news/2017-10-cold-temperatures-nasal-similarities-neanderthal.html#jCp

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