There are around 400 breeds and they vary dramatically in size, shape and behavior. But every one of the estimated 400 million dogs on the planet is descended from gray wolves that may have befriended Stone Age humans in eastern Asia as recently as 15,000 years ago. For this reason, dogs are a bit of an evolutionary puzzle.?
"Of the more than 5,500 mammals living today, dogs are arguably the most remarkable. The incredible physical and behavioral diversity of dogs – from Chihuahuas to Great Danes – is encoded in their genomes. It can uniquely help us understand embryonic development, neurobiology, human disease and the basis of evolution." said Eric Lander, director of the Broad Institute, in Cambridge, Massachusetts, and one of the team that cracked the genetic code of Tasha the Boxer bitch.
The Massachusetts scientists – backed by geneticists in Oxford and Cambridge, England – reported in Nature that they have a 99% accurate sequence of boxer genes to match against the earlier data from the poodle.?
The Maryland team compared genetic variations in the DNA of the two dogs with samples from Beagle, Labrador Retriever, German Shepherd, Old English Sheepdog, Alaskan Malamute and the Rottweiler as well as four types of wolves and a coyote. Systematic breeding and inbreeding has given humans hunting dogs, lap dogs, and guard dogs, but it has also led to a catalogue of inherited weaknesses in many breeds. In the end, according to Ewen Kirkness of the Institute for Genomic Research in Maryland, the study could lead to health gains for the animals.