Card from Dogstuff
It’s a good question. Dogs are generally understood to have been domesticated from wolves, at least 30,000 years ago. And for most of those many years, dogs were dogs, of no particular breed. They were, in other words, all mongrels.
Dog breeding only began 200 years ago, in England. Since that time, over 300 distinct breeds have been developed. And those breeds show more diversity, among more different traits, than any other mammal.
As NPR’s Ursela Goodenough points out, breeding programs have to work with whatever genetic material is there. All those dog breeders haven’t created new traits; they’ve just emphasized or limited certain ones that were already present.
So how is it that dogs’ DNA has so much variety encoded in it to begin with, just waiting for breeders’ attention?
Bottom line (see Goodenough’s post for the details): dogs are more prone to genetic mutations. The more mutations, the more possible variety. This is a characteristic scientists call evolvability, and dogs abound in it.
So the next time you take a look at your furry canid friends, take a moment to marvel at all the potential they represent.
Actually there are several breeds older than 200 years. Several Asian breeds, mostly from China and Tibet, go back over a thousand years. There are also several breeds in England and Europe that were developed between the 7th and 10th centuries. The Besenjii is considered one of the most ancient hunting dog breeds from Africa, dating back ten thousand years.
Good points. Goodenough (and I) should have specified dog breeds and breeding in the Western hemisphere.