Friday, July 17, 2009

Dwarf Dogs Defective By Design


Canine achondroplastic dwarf terrier with curved legs and big chest.

What is a poorly shaped canid with disproportionately short legs called?

For most of earth's history it was called "lunch."

If you can't run, you get eaten.

If you can't catch, you starve.

Somewhere along the line, however, humans decided that canine freaks were cute, and so they left them in the gene pool, and even began to breed them and create nonsense histories to rationalize their very existence.

Now, scientists have figured out that why short-legged canine breeds are short.

You and I, being true geniuses, would simply say "because their legs aren't very long," or perhaps "because of a genetic defect."

Scientists being scientists, of course, have to put a point on it, and so after a lot of money and time they have concluded it is because there is an extra copy of a single gene that codes for a growth-promoting protein called fibroblast growth factor 4 (FGF4).

"Although functional, the extra gene lacks certain parts of the DNA code, called introns, found in normal genes."

Great! So what?

Exactly.

The dog world has always known that short-legged dogs were genetic mutants. The fact that science has named the gene is interesting, but not particularly illuminating.

It should be said, however, that just because a dog is small does not mean it is "short-legged."

When we talk about short-legged dogs, we are talking about legs that are short relative to the rest of the body size.

The legs in these mis-shaped dwarf dogs are generally curved (i,.e. "benched") and the dog's chest is also quite large as well. As the scientists helpfully note in their paper:

Veterinary researchers already know that in certain dog breeds the development of long bones is curtailed due to calcification of growth plates, resulting in short legs with a curved appearance. The trait, called disproportional dwarfism, or chondrodysplasia, is an American Kennel Club standard for more than a dozen domestic dog breeds, including the dachshund, corgi, Pekingese and basset hound. This trait is distinct from the uniformly miniature size of toy breeds, such as the toy poodle.


Got it. We already knew it. Now we have named the gene.

Here's a thought: perhaps, in memory of Michael Jackson's passing, we could call in the "Billy Gene?"

Yes, I am going to hell. If you get there before me, keep my seat warm.


Human achondroplastic dwarves. Note the curved legs.
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