Maple Faces
Fans of Canada are seen with cut-outs of their national symbol of maple leaf ahead of their women's ice hockey gold medal game against U.S. at Sochi 2014 Winter Olympic Games, 20 February. Reuters

Ever wondered how every human face is so distinct and unique from another? A new study by scientists at the University of California, Berkeley, has found that this is due to evolutionary pressure that makes every person different from the other to facilitate easy recognition by people.

Behavioral ecologist Michael J. Sheehan, a postdoctoral fellow in UC Berkeley's Museum of Vertebrate Zoology explained that human beings have face to face interactions, unlike other species that interact through smell or vocalisation. A human being's identity is through his face and that is what has driven this "evolutionary trend."

Sheehan further stated that there is a particular part of the brain that is meant only to recognise faces and the study shows that human beings have been selected to be unique and recognisable. This allows us not just to be recognisable but to recognise others as well. This facilitates easy social interaction.

Michael Nachman, a population geneticist, professor of integrative biology and director of the UC Berkeley Museum of Vertebrate Zoology, said, "Human social structure has driven the evolution of how we look."

The study looked into why certain traits are unique in people, is it just by chance or has there been evolutionary selection to be more variable than they would be otherwise. The researchers found that facial traits are much different from bodily traits. This is due to the evolutionary process, said Nachman.

They found that genomes of people are different from people from around the world. The study found, "more genetic variation in the genomic regions that control facial characteristics than in other areas of the genome, a sign that variation is evolutionarily advantageous."

The genes that are responsible for the development of facial traits were more variable and less correlated than other traits. They assessed the army database of body measurements and found that the most variable traits are the eyes, mouth and nose.

They also looked in the data of the genome project which had sequenced 1,000 human genomes.

"Clearly, we recognize people by many traits -- for example their height or their gait -- but our findings argue that the face is the predominant way we recognize people," Sheehan said.

The study is published in the journal Nature Communications.