23 May 2016
ByAppeared in BioNews 852
Researchers have discovered four genes that play a part in determining the shape of people's noses.
The scientists behind the study, published in Nature Communications, say that the information could one day be used to create photofits of criminal suspects from their DNA. However, the paper says that each of the four genes identified accounts for only one percent of the natural variation in the specific aspect of nose shape it influences, meaning that DNA photofits will likely remain the stuff of science fiction for the foreseeable future.
The study analysed photographs of 6,000 Latin American people who also gave DNA samples. Fourteen different facial features were measured on the photos and the scientists picked out which genes were associated with those differences. Following this, half the participants were scanned to obtain more exact measurements of certain traits.
Using this approach, the team was able to identify four genes, GLI3, PAX1, RUNX2 and DCHS2, that are linked to nose shape, in particular nostril breadth, width and 'pointiness' of the nose. Researchers also found another gene, EDAR, involved in determining the shape of the chin.
Professor Andres Ruiz-Linares from University College London, who led the study, said that the genes had already been earmarked for their role in building bone and cartilage and in craniofacial development more generally. EDAR has been previously been linked to earlobe size, beard thickness and hair straightness, the paper says.
First author Dr Kaustubh Adhikari, added that the research 'brings us closer to understanding how genes influence the way we look, which is important for forensics applications'.
However, Professor Manfred Kayser, head of the genetic identification department at Erasmus University in the Netherlands, who was not involved in the study, told the Guardian that many more genes involved in face shape would need to be identified 'in much larger sized studies and replicated in independent samples before one can think of using them to predict facial features from DNA'. The paper notes that, to date, only two genome-wide association studies for facial features have been published.
Previous research had helped build the hypothesis that the shape of the nose reflects the environment in which humans evolved. For example, the comparatively narrower nose of Europeans 'has been proposed to represent an adaptation to a cold, dry climate', Professor Ruiz-Linares explained. 'Identifying genes affecting nose shape provides us with new tools to examine this question, as well as the evolution of the face in other species.'