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Curl-Locus (CURL)

Curly Coat Locus (CURL)

Cu Locus, Curly Hair, Curly Coat Trait, Straight Coat Trait, Wavy Coat Trait

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 other mutations such as coat length and furnishings that can also contribute to the overall look of a dog’s coat.

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These dogs have two copies of the normal gene and will have straight hair.


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.


These dogs have two copies of the mutation which typically results in a tight curly coat.

Additional Details


Autosomal Dominant (Incomplete Dominance)

Affected gene



Ch. 27


C.451 C>T


Cadieu E, Neff MW, Quignon P, Walsh K, Chase K, Parker HG, VonHoldt BM, Rhue A, Boyko A, Byers A, Wong A, Mosher DS, Elkahloun AG, Spady TC, Andre C, Lark KG, Cargill M, Bustamante CD, Wayne RK, Ostrander EA. Coat variation in the domestic dog is governed by variants in three genes. Science. 2009 Oct; 326(5949):150-3. [PubMed: 19713490]