Seven Genetic Differences among all Dog Breeds

While the physical difference between a great dane and a chihuahua is apparent, the genetic makeup of all dog breeds is pretty much the same. In fact, there are only seven genetic variations that differentiate the thousands of dog breeds living today.

Spaniels have notably floppy ears, basset hounds have extremely short legs, and St. Bernards are large and big boned. Not to mention Chihuahuas.

But a new study reports that the physical variance among dog breeds is determined by differences in only about seven genetic regions. These seven locations in the dog genome explain about 80 percent of the differences in height and weight among breeds, said Carlos Bustamante, a geneticist at Stanford University and one of the study’s authors.

“We are trying to identify genes that might be important in governing the differences between different dogs,” Dr. Bustamante said. The project was conducted jointly by researchers at Stanford, Cornell University and the National Human Genome Research Institute.

A stronger understanding of dog genomes may shed more light on how genes are involved in disease processes, said Elaine Ostrander, a geneticist at the National Human Genome Research Institute and another author of the study. For instance, it has been hypothesized that osteosarcoma, a type of bone cancer, is a common disease in long-legged breeds, she said.

Discoveries about dog genomes may in turn help researchers understand the role of genetics in human disease.