Three Genes Account For Dog Coat Differences
Variants in just three genes acting in different combinations account for the wide range of coat textures seen in dogs — from the poodle's tight curls to the beagle's stick-straight fur. A team led by researchers from the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health, reports these findings today in the advance online issue of the journal Science.
"This study is an elegant example of using genomic techniques to unravel the genetic basis of biological diversity," said NHGRI Scientific Director Eric Green, M.D., Ph.D. "Genomics continues to gain new insights from the amazing morphological differences seen across the canine species, including many that give clues about human biology and disease."
Until now, relatively little was known about the genes influencing the length, growth pattern and texture of the coats of dogs. The researchers performed a genome-wide scan of specific signposts of DNA variation, called single-nucleotide polymorphisms, in 1,000 individual dogs representing 80 breeds. These data were compared with descriptions of various coat types. Three distinct genetic variants emerged to explain, in combination, virtually all dog hair types.
"What's important for human health is the way we found the genes involved in dog coats and figured out how they work together, rather than the genes themselves," said Elaine A. Ostrander, Ph.D., chief of the Cancer Genetics Branch in NHGRI's Division of Intramural Research. "We think this approach will help pinpoint multiple genes involved in complex human conditions, such as cancer, heart disease, diabetes and obesity."
Artificial selection, at the heart of breeding for desirable traits in domesticated animals, has yielded rapid change in a short span of canine history. While researchers estimate that modern dog breeds diverged from wolves some 15,000 years ago, the genetic changes in the dog genome that create multiple coat types are more likely to have been pursued by breeders in just the past 200 years. In fact, short-haired breeds, such as the beagle, display the original, more wolf-like versions of the three genes identified in the study.