Short tail 3

This short tail, bobtail or even absent phenotype is characteristic of breeds such as the Manx or Pixiebob cat.

Definition

The short tail trait in Manx and Pixiebob cats is characterized by a variety of phenotypes ranging from the complete absence of a tail to short tails and bobtails. This distinctive characteristic is determined by genetic mutations in the TBXT gene (formerly known as the Brachyury gene), which encodes a key protein in notochord development in vertebrates, i.e., in the formation of the caudal vertebrae that make up the tail.

Genetic basis

The final expression of this trait is influenced by interactions with variants in different genes that affect vertebral development and the physical structure of the cat. In this case, we studied the c.1166del deletion of the TBXT gene. This trait is inherited in an autosomal dominant manner, meaning that a single copy of the variant is sufficient for cats to express the trait.

Other relevant information

An interesting fact is that the tail length in Manx and Pixiebob cats does not follow a uniform pattern. Within the same litter, there can be cats with completely absent tails (“rumpy”) and others with almost complete tails (“longie”). This variability is due to incomplete penetrance and variable expressivity of mutations in the TBXT gene.

Bibliography

Buckingham KJ, McMillin MJ, Brassil MM, et al. Multiple mutant T alleles cause haploinsufficiency of Brachyury and short tails in Manx cats. Mamm Genome. 2013;24(9-10):400-408.