Like their owners, our noses come in a variety of shapes and sizes. The reason, according to recently published research, may lie in our evolutionary past.
In a study published in PLOS Genetics in March, scientists from Penn State found a correlation between the climate one’s ancestors lived in and one’s nostril width. Colder climates may have favored longer, narrower nostrils, while the opposite case appears more in warmer locales.
This is based off of a longstanding hypothesis that nose shape may have evolved with climate due to the nose’s role in warming and humidifying inspired air, said Arslan Zaidi, a postdoctoral genetics scholar and one of the study’s authors.
And our noses, because they’re exposed to the external environment, may be more susceptible to natural selection pressures, Zaidi said. Thus, they may evolve faster. Knowing how our noses evolved could play a role in how we understand human health.
“Looking at the variation of these genes is going to paint a cleaner picture of what exactly happened,” Zaidi said. “It could potentially have consequences for disease risk. If I have a wider nostril and I’m living at a higher latitude or someplace where it’s colder and drier, does it affect my respiratory health? It may not affect it to a drastic level, but it could be something of interest to public health.”
Zaidi’s team wanted to pinpoint if the trait was heritable — or could be chalked up to more than chance variations over time — and find more evidence connecting a snout’s shape with the climate of its owner’s ancestors. The team found both.
“We found that width of the nostril, out of all the traits we looked at, shows a signature of greater differentiation across populations than expected by genetic drift,” Zaidi said.
In doing so, the researchers measured seven traits among participants whose parents were born in regions consistent with their genetic ancestry. They also compared other traits such as skin pigmentation.
Of the seven they studied, only one (nostril width) showed significant differences compared to genetic drift — or chance variations. This matters, Zaidi said, because it helps to disentangle perception from reality.
“There are social implications to studying this,” he said. “What we have done is looked at differences and similarities. When we find a difference in nostril width, people tend to focus on the differences and forget about the similarities, which are far larger than the differences are.”
Zaidi added that only about 10 percent of variability exists between populations. In other words, we’re more similar than our faces (and noses) suggest.
“That’s important to remember because, especially now in today’s social climate, there is a reason for these differences,” Zaidi said. “So when you put it into an evolutionary context, it helps to demystify the concept of race.”
Such studies, Zaidi said, can help us understand humanity from both a genetic and sociological perspective.
“Often it’s like, ‘You are different from me because you look different,’ but that’s only on the surface,” he said. “There’s so much else to us. Why ignore all of that?”