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Study reveals genetic changes linked to flat-faced dogs

A study of dog DNA has revealed a genetic mutation linked to flat face shapes such as those seen in pugs and bulldogs.

Flat faced dogs

25 May 2017

The popularity of the French bulldog and Pug belies the morbidities caused by their flattened face shape such as respiratory distress and ocular trauma.

Dr Jeff Schoenebeck and colleagues from The Roslin Institute analysed DNA samples from 374 pet dogs of various pedigree and mixed breeds, which were being treated at the Royal (Dick) School of Veterinary Studies. All of the animals underwent body scans as part of their care, producing detailed 3-dimensional images of the dogs’ heads. These high-resolution images – called CT scans – enabled the researchers to take precise measurements of the shape of the dog’s skull.

By comparing the dogs’ genetic information with measurements of their skulls, the team were able to pinpoint genetic variations that are associated with different head shapes. One variation – found to disrupt the activity of a gene called SMOC2 – was strongly linked to the length of the dog’s face. Animals with the mutation had significantly flatter faces, a condition called brachycephaly.

Babies are sometimes born with brachycephaly too, though little is known about its causes. Scientists say screening children for changes in the SMOC2 gene could help to diagnose the condition.

Our results shed light on the molecular nature of this type of skull form that is so common and popular among dogs.

Dr Jeffrey SchoenebeckLead researcher

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Original Publication:Thomas W. Marchant, Edward J. Johnson, Lynn McTeir, Craig I. Johnson, Adam Gow, Tiziana Liuti, Dana Kuehn, Karen Svenson, Mairead L. Bermingham, Michaela Drögemüller, Marc Nussbaumer, Megan G. Davey, David J. Argyle, Roger M. Powell, Sérgio Guilherme, Johann Lang, Gert Ter Haar, Tosso Leeb, Tobias Schwarz, Richard J. Mellanby, Dylan N. Clements, Jeffrey J. Schoenebeck. Canine Brachycephaly Is Associated with a Retrotransposon-Mediated Missplicing of SMOC2. Current Biology. Published online 25th May 2017