Lowdown on the Low-down

My daughter, who recently graduated with an undergraduate degree in biology, explored the genetic components of one aspects of the dog's anatomy--the shape of its nose. The premise behind her theoretical experiment was that by changing the one gene that is responsible for the shape of a nose, she could induce either "pug" or "snout" noses in lab rats.

The research was, of course, hypothetical so we will never know if she is right but recent research on the gene responsible for short legs in dachshunds may provide a clue. It turns out there is a single extra copy of a gene that is responsible for the breed's short legs.

According to a post of the TierneyLab blog of the New York Times, Heidi Parker, a geneticist at the National Institutes of Health's National Human Genome Research Institute, recently reported in Science, that the extra copy of the gene was acquired by mutation at least 300 years ago.

This extra gene causes overproduction of a protein that actually stunts the growth of the legs of such breeds as dachshunds and basset hounds. Once the gene appeared, breeders could select for it when looking to breed dogs with short legs. The basset hound was intentionally "designed" with short legs, according to Parker, so that people on horse back could keep up with it during hunts.

The dachshund's long body and short legs are, of course, ideal for burrowing into holes to flush out vermin--the job for which they were bred--but also have created the tendency in the breed for members to develop spinal issues. Ironically these issues are often related to those short legs--back injuries resulting from jumping on or off furniture.

Owners of short legged breeds usually adore their pooches just for this trait, so it is interesting to note that those low slung profiles are really developmental disorders.