Types of Rex coats

Genetic symbol

Straight hair = (ss)

Heterozygous = (Ss)

Homozygous = (SS)

Genetic Expressions of the Selkirk Rex

In the Selkirk Rex, the terms homozygous, heterozygous, and straight-coated refer to genetic variants that influence the degree of curl in the coat. This is all linked to the presence or absence of the gene responsible for curls, often referred to as the S gene.

Homozygous Selkirk Rex (S/S)
A homozygous cat carries two copies of the S gene, one inherited from each parent. This results in a very curly coat, often denser and more tightly curled than in other expressions. These cats display visible curls over the entire body, including the whiskers.

Heterozygous Selkirk Rex (S/n) or (S/s)
A heterozygous cat carries one copy of the S gene and one copy of a “normal” gene (n). The coat is wavy or partially curly, sometimes with smoother areas. Curl intensity can vary significantly from one individual to another.

Straight-Coated Selkirk (n/n) or (s/s)
A cat that does not carry the S gene (two non-rex copies) has a straight coat with no curls. Although it comes from Selkirk Rex lines, it resembles a traditional cat in terms of coat texture. The coat may be long or short.