Hair curl is an incomplete dominant characteristic caused by a mutation in the KRT71 gene.  Incomplete dominance refers to the fact that a dog can carry one copy of the gene which will result in a moderately curly (known as “wavy”) coat or two copies of the mutation which will result in a tightly curled coat.  Dogs lacking the mutation will typically have straight hair.  This particular mutation can be found prevalently in some breeds that typically display a curly coat.  The hair curl mutation can also be accompanied by the other mutations such as coat length and furnishings that can also contribute to the overall look of a dog’s coat.

• Airedale Terrier
• American Water Spaniel
• Bichon Frise
• Border Collie
• Boykin Spaniel
• Chesapeake Bay Retriever
• Chihuahua
• Dachshund
• Havana Silk Dog
• Havanese
• Kerry Blue Terrier
• Kuvasz
• Leonberger
• Maltese
• Pharaoh Hound
• Portuguese Water Dog
• Soft-Coated Wheaten Terrier
• Welsh Terrier
• Wire Fox Terrier

A (CLEAR/NORMAL): These dogs have two copies of the normal gene and will have straight hair.

B (CARRIER/AFFECTED): These dogs have one copy of the normal gene and one copy of the mutation associated with a curly coat type.  Due to incomplete dominant expression, these dogs can have a “wavy” or moderately curly coat that is in the spectrum somewhere between a curly and a straight coat.  They will also if bred, pass the mutation to 50% of its offspring, on average.

C (AT RISK/AFFECTED): These dogs have two copies of the mutation which typically results in a tight curly coat.