Stumpy Tail (Bobtail - Brachyuria Dog)
Stumpy tail (Bobtail - Brachyuria) is a natural form of shortened tail in dogs.
General Information
- The stumpy tail occurs in some breeds: Australian Shepherd, Australian Stumpy Tail Cattle Dog, Braque du Bourbonnais, Brazilian Terrier, Epagneul Breton, Jack Russell Terrier, Mudi, Polish Owczarek Nizinny, Pyrenean Herding Dog, Schipperke, Spanish Water Dog, Welsh Corgi Pembroke, etc.
- This trait is homozygous lethal. Dogs with two copies of the mutated gene die before birth.
- Breeding of two heterozygous animals (with stumpy tail) usually results in a reduced litter size, as 25% of the litter are homozygous and die before birth.
- Animals with stumpy tail should therefore only be bred to animals with normal tail.
Test Information
Locus Information: T-gene B-Allele
This mutation test detects a change of a single base pair in the T gene. (Attention: There are also dog breeds in which the stumpy tail is not caused by this mutation.)
Genotype and Lab Report
Inheritance: autosomal dominant.
→ Animals with one or two copies of the gene (B/b, B/B) show the phenotype stumpy tail (bobtail). Homozygous animals (B/B), however, die before birth. Animals with no copy of the gene have a "normal" long tail.
Genotypes
b/b = Two copies for 'normal tail'
No disposition for stumpy tail (Bobtail), the dog has a "normal" long tail.
B/b = One copy for bobtail and one for 'normal tail'
The dog has a stumpy tail (bobtail) and passes this trait on to 50% of its offspring.
B/B = Two copies for bobtail
Dogs that are homozygous for stumpy tail (bobtail) die before birth.
Appearance
Stumpy tail (Bobtail)
The dog shows a shortened tail.
Possible genotypes:
B/b
'Normal tail'
The dog shows a 'normal' long tail.
Possible genotypes:
b/b
Literature
Haworth, K., Putt, W., Cattanach, B., Breen, M., Binns, M., Lingaas, P., Edwards, Y.H.: Canine homolog of the T-box transcription factor T; failure of the protein to bind to its DNA target leads to a short-tail phenotype Mammalian Genome 12:212-218, 2001. Pubmed reference: 11252170. DOI: 10.1007/s003350010253
Hytönen, M.K., Grall, A., Hédan, B., Dréano, S., Seguin, S.J., Delattre, D., Thomas, A., Galibert, F., Paulin, L., Lohi, H., Sainio, K., André, C.: Ancestral T-box mutation is present in many, but not all, short-tailed dog breeds. J Hered 100:236-40, 2009. Pubmed reference: 18854372. DOI: 10.1093/jhered/esn085
Further information is available at Online Mendelian Inheritance in Animals.