Canine Research Continues
By Al Magaw
It’s gratifying to see scientific research on our canine friends continuing – in a recent study, reported Aug 10/2010 in Science Now, further research has brought more understanding to how breeds have developed in virtually an evolutionary moment in time. While the report doesn’t deal specifically with sled dogs, the conclusions apply as well to our racing compatriots as it does to great danes, sheep dogs, chows or spaniels. Large or small, short hair or long, the basics are the same for all dogs. A team led by “Carlos Bustamante a comparative geneticist at Stanford University in Palo Alto, California, and Elaine Ostrander, a comparative geneticist with NHGRI, analyzed genetic information from 915 domestic dogs representing 80 different breeds. The researchers compared the dogs’ DNA, looking for sequences that differed by a single base, known as single-nucleotide polymorphisms. Once they found out where the DNA differed, they compared those differences between dogs with, for example, short versus long legs or perky versus droopy ears.”
The researchers identified “51 regions in the genome that contributed to physical variation among the breeds. These regions can be clumped into larger areas of the genome called quantitative trait loci, which are known to contain genes that produce a specific physical effect, such as shaggy hair” “Depending on which traits are compared, genetic differences in two to six of these regions,can account for about 80% of the variation in physical characteristics among dogs, says Bustamante” most likely the ” selective pressure caused by human-directed breeding, the researchers conclude.
Co-author Heidi Parker, a geneticist at NHGRI, says that because humans initially bred dogs for specific traits—say, smaller body size or calm temperament—selection created a population “bottleneck” that narrowed the genetic variation in offspring, leaving them with just a few specific clusters of variable genetic regions. Variable genes within these clusters, such as those that govern snout length or leg length, were then selected” “by humans to create the dog breeds we recognize today” “The study validates the idea that a relatively small amount of genetic variance can lead to a large degree of physical diversity, says Jeffrey Phillips, a veterinary geneticist at the University of Tennessee, Knoxville. The findings corroborate what many in the field suspected but do so with “a very, very impressive sample size,” he says. “It’s a wealth of information” he concluded. My interest in this aspect of dog breeding continues to grow and I look forward to learning more about it. It certainly helps explain why in less than a century, the alaskan husky, through environmental pressure and selective breeding, has gone from being a cross bred mutt to a super performing specific breed recognisable by it’s DNA.
Al Magaw is a musher from Salmo, BC. Al keeps a medium sized kennel of 20 – 45 alaskan huskies as well as several pet dogs of various breeds. Al has been training and racing for the last 33 years. Before becoming involved with sled dogs, Al, along with his family, kept and competed with horses for many years. Al can be reached through his website athttp://www.spiritofthenorthkennels.com Al is a guest blogger for Denver Dog Works and can be reached through our website athttp://www.denverdogworks.com