Curly Coat (KRT71 gene, Devon Rex)

This type of coat is also known as "Rex" phenotype and stands out for being a curly coat instead of the common straight coat.

Definition

The curly coat characteristic of breeds such as the Devon Rex is further characterized by the absence of guard hairs and a reduction in the length and thickness of the undercoat hairs. This phenotype is determined by the KRT71 gene, which encodes a keratin protein essential for the maintenance of the hair structure. Alterations in this gene cause significant changes in the coat, resulting in unique phenotypes such as the curly coat of Devon Rex cats or even the absence of hair in other breeds.

Genetic basis

The genetic variant associated with this phenotype involves a complex insertion and deletion mutation in the KRT71 gene. The allele responsible for the curly coat is known as KRT71^re. The following allelic series has been proposed in the KRT71 gene: KRT71(+) > KRT71(hr) > KRT71(re), where the + symbol represents the wild type and hr is related to the hairless phenotype of the Sphynx cat. The curly coat caused by the KRT71^re allele follows an autosomal recessive inheritance pattern, meaning that two copies of the variant are required for the trait to be expressed. However, the presence of a single copy of the variant can be transmitted to offspring with a 50% probability.

Other relevant information

Although the curly coat is the most visible trait, mutations in the KRT71 gene can have other implications for hair follicle health and structure. Genetic variability in these mutations can result in different degrees of curl and coat texture.

Bibliography

Gandolfi B, Outerbridge CA, Beresford LG, et al. The naked truth: Sphynx and Devon Rex cat breed mutations in KRT71. Mamm Genome. 2010;21(9-10):509-515.