New Curly Hair Gene Variant With Possible Link to Follicular Dysplasia Found in Curly-Coated Retrievers
Researchers find new curly hair gene variant. The gene may be linked to a type of hair shaft structure which causes coat breakage and follicular dysplasia.
The news is not good for we curly-coated retriever owners and breeders who hoped for a genetic marker test to avoid producing dogs with follicular dysplasia, commonly referred to as coat patterning or patterned baldness.
Researchers have found the allele which causes curly hair in Curly-Coated Retrievers and Irish Water Spaniels. The new allele, named curly allele c2, is different from the c1 allele found in most curly dogs, said Dr. Tosso Leeb, professor of genetics at the University of Bern, Switzerland.
Poodles and many other curly breeds are homozygous for the c1 allele which gives them a curly coat with good hair quality. Curlies and IWS are homozygous for the c2 allele.
"The c2 allele gives rise to curly hair that has a tendency to break. With the c2 allele, the hair shafts are not as tightly linked to their follicles as they are in dogs with the c1 allele (or in dogs with straight hair)," Leeb stated.
"Therefore, this special type of genetic makeup predisposes all Curly Coated Retrievers to follicular dysplasia."
If we want to retain the unique coat of a curly, we probably cannot breed away from the c2 allele.
As breeders and owners, we all know follicular dysplasia differs in its severity. Some curlies appear never to have any hair loss while others can have large bald patches on various parts of their bodies. But please remember: just because a breed is predisposed to developing a condition does not mean it necessarily will.
This difference in hair quality among Curly Coated Retrievers is due to other modifying factors which may be genetic and/or environmental, Dr. Leeb said.
Unfortunately, the problem is too complex to be solved with today's technology and resources, he said.
In the future researchers might be able to identify other genes affecting the follicular structure in curlies and develop a marker test.
What can we as breeders do? Basically, the same thing we have been doing all along: selecting on phenotype and hoping for the best.
"My recommendation to breeders is the following: When selecting breeding animals you should preferentially choose dogs with a good hair quality and no signs of hair loss...," Dr. Leeb said. "You have to expect that the hair of Curlies may be more susceptible to mechanical friction (e.g the rubbing of a harness might cause substantially more hair breaks and hair loss on a Curly Coated Retriever than in most other dogs)."
For now, Leeb's research into follicular dysplasia in curlies is complete.
Link to an abstract of the researchers' article in Animal Genetics:
Another research group happened to identify the new curly hair gene variant at about the same time as the Swiss group. The link to the research article abstract for that group is here: