The colour scale represents climatic variation in temperature and humidity, to show that narrower nares are favoured in cool-dry climates while wider nares are favoured in hot-humid climates. Colours in between represent intermediate phenotypes. 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.īlue boxes represent alleles for narrower nares while red boxes represent alleles for wider nares. The authors say that suggests variations in those traits have been influenced by natural selection. 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. 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. But while previous studies were based on measurements from human skulls, he says, the new study looked at nose shape itself. “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.
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