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Thursday, August 19, 2010

Dog brains altered by breeding

When you breed a species to look like a chihuahua or a mastiff or every size and shape in between, you have to alter a lot of body features. Taryn Roberts and Paul Mcgreevy of the University of Sidney, and Michael Valenzuela of the University of New South Wales have found that body shape isn’t all that selective breeding has changed. It turns out that dog brains have been altered by breeding as well.

The researchers used magnetic resonance imaging (MRI) to look at a variety of canine brains and found some significant differences. In particular, the brains of short-snouted dogs like pugs are rotated forward by up to 15 degrees. The olfactory lobe (which processes smells) was also displaced compared to dogs with longer snouts.

Dogs have a remarkably flexible genome to be able to withstand such extreme changes and yet remain dogs. Valenzuela and the other researchers are interested in determining whether these differences in brain position translate to differences in brain function, and ultimately in behavior.