Portuguese water dogs play key role in genetics research

Nobody knows Bo like geneticists know Bo.

The Obamas may have accepted Bo the Portuguese water dog as First Puppy because of the breed's hypoallergenic coat, but the dogs are also the most genetically studied breed in the world.

Thanks to their remarkable history, the dogs have been the source of key insights into the function of certain canine genes, including determining a dog's size and whether it is susceptible to a devastating disease. Those insights also have offered clues to researchers looking into human diseases.

"Dogs have many of the same diseases that humans have. There is great hope these [findings] will translate to humans," said Kevin Chase, senior researcher at the Georgie Project at the University of Utah, which studies Portuguese water dog genetics. (Georgie was a water dog belonging to the project's founder.)

A series of lucky breaks has made the breed ideal for genetic research. First, all American Kennel Club-registered water dogs came from a tiny founding group of about 30 animals starting in the 1930s. That means the amount of genetic variation from animal to animal is small compared with breeds that have many founders.

In addition, the breed standard for water dogs allows for a lot of physical variation. Registered Portuguese water dogs can be big or small. They can have curly hair or wavy. They can be black. They can have bits of white hair, as Bo does.

That variety allows geneticists to look at the genomes of big water dogs vs. small ones, seeking out regions where genetic patterns differ. When they find genes that seem to have something to do with size, researchers can apply that idea to other breeds, from mastiffs to toy poodles, and see if the pattern holds.

Doing just that, geneticists found that small dogs shared a snippet of DNA near the IGF1 gene, which helps control growth, on chromosome 15. They think that snippet suppresses the IGF1 gene, which keeps dogs small.

The next step was to look in that area for genes affecting diseases of growth regulation, such as cancer, said geneticist and cancer researcher Elaine Ostrander, head of the Dog Genome Project at the National Human Genome Research Institute in Bethesda, Md.

"The genes we have found are generally responsible for diseases in humans," she said.