Physical and behavioral traits in dogs are amongst the most variable within a single species. The amazing versatility and variability within Canis familiaris is astounding--even more so since all of these observable differences were achieved by selective breeding by humans. The underlying factors that contribute to this variation has not been understood, but a new report in the current issue of Genetics reports data that begins to explain these familiar phenomena.
Dogs originally derived from the wolf more than 15,000 years ago -- a blink of the eye in evolutionary terms. Selective breeding produced dogs with physical and behavioral traits that were well suited to the needs or desires of their human owners, such as herding or hunting ability, coat color and body and skull shape and size. This resulted in the massive variance seen among the more than 350 distinct breeds that make up today's dog population. Until now, the genetic drivers of this diversity have intrigued scientists who have been trying to explain how and why the difference in physical and behavioral traits in dogs changed so rapidly from its wolf origins.
An international team of researchers, which included scientists at the National Human Genome Research Institute, the University of Utah, Sundowners Kennels in Gilroy, California and Mars' Waltham Center for Pet Nutrition in the United Kingdom, studied simple genetic markers known as Single Nucleotide Polymorphisms, or SNPs, to find places in the dog genome that correlate with breed traits. Because many traits are "stereotyped" -- or fixed within breeds -- researchers can zero in on these "hot spots" to see what specific genes are in the area that might contribute to differences in traits.
The abstract and the paper can accessed here.