Apr 15, 2007
What's the difference between the largest dog in the world and the smallest dog in the world? Aside from the obvious (284 lbs, give or take 27 oz), the answer is: not a lot.
Despite the fact that "Hercules" (284 lbs) is 200 times more dog than "Danka" (27 oz), the difference is merely a single genetic variant of the IGF1 gene, a variant which small dogs possess and large dogs lack.
An international team of 21 geneticists working with the National Human Genome Research Institute, published its findings last Friday in the journal Science after having studied DNA samples of over 3,000 dogs and 143 breeds.
Many of these samples were taken by swabbing the subject's cheek with one hand while waving a tennis ball with the other as a distraction (clever lot, those geneticists).
Dogs proved to be the ideal subjects due to their variety of sizes, "the greatest diversity in body size of any mammalian species." 1 And of course, dogs respond much better to tennis balls than, say, pea plants do.
The researchers' findings have been hailed as a great advancement in our understanding of certain genetic proclivities such as prostate cancer, also linked to the IGF1 gene.
Future aims of the study are to expand into other aspects of canine morphology such as leg length and skull shape.
Who knows, maybe one day we may actually figure out why dogs have thumbs.  |
UPDATE:
