Thursday, December 07, 2006

The Lundehund and the genomic plasticity of canines

Years ago few cared much about the biology of dogs. They are, after all, so common - and so "artificial". It was far more interesting to study wolves or sharks.

Times change. Dogs are weird. They are the among the most successful large terrestrial mammals in history based upon population, range, and their almost complete lack of predators (humans eat dogs in South Korea and in some parts of China). It is likely, given our longstanding commensal relationship, that they have altered human evolution. They have extraordinary variability in aging rates for a single species. They can read human faces and mimic human expressions and emotions. They're very hard to clone, and they have a weirdly plastic genome. Consider the Lundehund:
Damn Interesting � The Norwegian Puffin Dog

...To enhance traction on slippery rocks, and gripping in tight places, the Lundehund is a polydactyl (multi-toed) dog. Instead of the normal four toes a foot, the Lundehund has six toes, all fully formed, jointed and muscled. Polydactyl dogs are not terribly uncommon, but in most breeds the extra toes are dew-claws - non-functional vestigial toes, not the fully formed variety of the Lundehund. The dog uses these extra toes to gain purchase and haul itself along in positions where only the sides of its legs are touching the rock, a fairly common occurrence while wiggling through tight spots. They also help the dog gain additional traction while scrambling around on steep, often slippery cliffs...
The Lundehund is a weird animal, though much of its adaptations may come down to a connective tissue disorder which is also seen in humans (hyperelastic joints). Canine biology is fascinating indeed. The more we look at the history of human "breeds" 30,000 to 100,000 years ago the more interesting canine "breeds" becomes ...

No comments: