Bobtail test

Does your dog have a natural bobtail or is it docked? - Gene test for short tail gives an quick answer...

The short tail phenotype (anury and brachyury) in dogs has been known for many years. The causative mutation in the T-box transcription factor T has been previously identified in Pembroke Welsh Corgis. In our recent study, we discovered that the bobtail mutation is the genetic cause for the short tail phenotype in other dog breeds too.

Our genetic analysis covered 379 dogs within 20 different breeds. Among the analysed breeds 17 breeds presented the known T-box mutation in short tail animals with a full penetrance. No homozygous T-box affected animals were found confirming the lethal status of the inactivating mutation in several dog breeds. The mutation responsible for the short tail shows a dominant mode of inheritance.

The following breeds can be tested for the natural bobtail mutation:

- Australian Shepherd
- Australian Stumpy Tail Cattle Dog
- Austrian Pinscher
- Bourbonnais Pointer
- Brazilian Terrier
- Brittany Spaniel
- Croatian Sheepdog
- Danish/Swedish Farmdog
- Jack Russel Terrier
- Karelian Bear Dog
- Mudi
- Polish Lowland sheepdog
- Pyrenean Shepherd
- Savoy Sheepdog
- Schipperke
- Spanish Waterdog
- Swedish Vallhund

The cut of the tail, also called caudectomy, is prohibited in many countries. Owners are required to prove that the short tail is natural in order for the dog to be registered and to take part in dog shows.

Genoscoper has developed a DNA test for this mutation. The test helps breeders and veterinarians to check by a simple way that the short tail is natural.

The test results will be interpreted as follows:

NORMAL: The dog carries two copies of the normal gene and has a normal tail.

HETEROZYGOTE: The dog carries one copy of the bobtail mutation and because of the dominant inheritance is a natural bobtail. Heterozygous dogs will pass over the defect to approximately 50% of their offspring.

Homozygous dogs have two copies of the mutated gene but it seems that homozygous dogs are not capable of surviving.

References:

Hytönen MK*, Grall A*, Hédan B, Dréano S, Seguin SJ, Delattre D, Thomas A, Galibert F, Paulin L, Lohi H, Sainio K and André C. Ancestral T-box mutation is present in many but not all short-tailed dog breeds. J Hered 100(2):236-40, 2008.