Variations in nose shape developed as a result of natural selection in response to different climates, new study suggests
Human noses have been shaped by climate, according to research probing variation in the human snout.
Researchers say their findings back up the theory that wider nostrils developed in populations living in warm, humid conditions, while populations living in high latitudes, such as northern Europe, developed narrower nostrils as an adaptation to the chilly, dry conditions.
People have thought for a long time the difference in nose shape among humans across the world may have arisen as a result of natural selection because of climate, said Arslan Zaidi, co-author of the study from Pennsylvania State University. But while previous studies were based on measurements from human skulls, he says, the new study looked at nose shape itself.
Writing in the journal Plos Genetics, researchers from the US, Ireland and Belgium describe how they began to unpick variations in nose shape by using 3D facial imaging to take a host of measurements from 476 volunteers of south Asian, east Asian, west African and northern European ancestry.
The results revealed that only two out of seven nose-related traits were found to differ more between the populations than would be expected from the impact of random, chance changes in genetic makeup over time. The authors say that suggests variations in those traits have been influenced by natural selection.
With further analysis, based on data from participants of west African and European ancestry, confirming that nose shape is highly heritable, the team looked to see if there was a link between nose shape and climate.