Aug 31, 2009 - News

Study Sniffs Out Genes Behind Dog Hair

New genetic research may explain why Fluffy is so fluffy.

A study led by researchers at the National Human Genome Research Institute scanned 1,000 dogs from 80 breeds, looking for genes associated with different hair types: curly, wavy, straight, wiry, long, and any combination of these. Their results, published online last week in Science, show that variations in just three genes account for nearly all types of coats worn by man’s best friend.

Dog Hair

The study found that purebred dogs with similar hair types were found to have similar variations in three particular genes, RSPO2, FGF5, and KRT71.

A particular variation in the RSPO2 gene was linked to wiry hair in a pattern that gives dogs a mustache and eyebrows, such as in a schnauzer.

A variation in the FGF5 gene was associated with long hair, whether silky or fluffy, like that in a Pomeranian. Variations in the KRT71 gene seem to affect the extent of hair curl in dogs like Irish water spaniels.

Previous studies have shown that the FGF5 and KRT71 genes also affect hair type in cats and mice, suggesting that their effects may be relevant to all mammals, including humans.

Short Hair, Long Hair, and In Between

Some dogs have all three variations identified by the researchers, including Portuguese water dogs, a breed you may have seen taking walks on the White House lawn.

Short-haired dogs like beagles, who don’t exhibit any different types of hair studied by the researchers, all seem to have the ancestral versions of the FGF5, RSPO2, and KRT71 genes. The study also found that wolves carry the non-mutated forms of these genes, suggesting that the different hair types evolved after the evolutionary split between the two canine subspecies.

Despite what we know about the genetics of hair type in dogs, little is known about what makes human hair straight, wavy, curly, frizzy, kinky, woolly, or helical. While hair type in dogs is easily classified, studying human hair is not as simple. Some scientists have suggested characterizing hair by curl ratios and other measurements, but our diverse biological background poses a challenge in classifying human hair types for research.

This study could help researchers better understand the genetics of hair type in humans. It has also unleashed new possibilities for human disease research because these three genes that affect dogs’ coats also regulate many other processes in living organisms, allowing researchers to study how powerful genes interact.

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