New Delhi: The size and shape of your nose may not be genetically inherited from your parents but evolved, at least in part, in response to the local climate conditions, Claim researchers. The nose is one of the most distinctive facial features, which also has the important job of conditioning the air that we breathe. Differences in the human nose — big, small, broad, narrow, long or short, turned up, pug, hooked, bulbous — may have accumulated among populations through time as a result of a random process called genetic drift. However, the study led by researchers from Pennsylvania State University in the US, showed that the width of the nostrils and the base of the nose measurements differed across populations more than could be accounted for by genetic drift, indicating a role for natural selection in the evolution of nose shape in humans. To show that the local climate contributed to this difference, the team focused on nose traits that differ across populations and looked at geographical variation with respect to temperature and humidity. The results, appearing in the journal PLOS Genetics, revealed that the width of the nostrils is strongly correlated with temperature and absolute humidity.