
One of the most amazing things about canines is the astounding range of sizes and shapes they come in. From Saint Bernards to Chihuahuas - and everything in between – there’s a dizzying array of physical variations. This explosion of varieties has happened extraordinarily quickly in terms of evolutionary timescales due to relentless selective breeding by humans and, as a result of our genetic meddling, the dog is now the physically most diverse land animal on the planet.
With the multitude of shapes and sizes in the canine kingdom, you may be surprised to note that only six or seven locations in a dog’s genetic code can explain about 80% of the differences in height and weight among dog breeds. In comparison, in studies on humans, like those conducted by Carlos Bustamente, professor of genetics at Stanford, differences in height and weight in humans are controlled by hundreds if not thousands of genetic variations. More...