"A study of inherited short tail and taillessness in Pembroke Welsh corgi"

This study focused on researching if the natural short tails of Pembroke Welsh corgis are related to spinal defects, analyzing anatomical defects of two tailless puppies, and investigating a mutation in the T-gene (C296G). 

 

Natural short-tailed corgis       The natural short tail of the Pembroke Welsh corgi largely separates it from the long-tailed Cardigan Welsh corgi. For centuries, there has been a preference for short tails in corgis. However, due to tail docking, people never specifically bred for it. It wasn't until tail docking became illegal in the 1980's in numerous European countries that the natural short tail became increasingly bred for. In 2001, it was discovered that a recessive mutation in the T-gene caused the short tail in Pembroke Welsh corgis. The dogs studied were both heterzygous, suggesting that the homozygous form for the mutation was fatal. Additionally, studies on the Manx cat and mice have shown that these animals with natural short tail were more likely born with spinal issues.

The spines of 19 adult corgis were studied and analyzed. All corgis had naturally short tails and had parents with short tail and long tail. If any inherited spinal defects were discovered, the dog's littermates would be examined.

None of the corgis had inherited spinal problems, so no littermates were examined. Two dogs, however, were diagnosed with osteoarthritis. 

All the corgis were assumed to be heterozygous for the mutation. This means that natural short tail is most likely not associated with congenital spinal abnormalities. 

 

Tailless corgis                                                                                                                                                       In 2002 and in 2005, two Pembroke Welsh corgi puppies from different litters were discovered to have numerous abnormal anatomical defects. Both puppies were homozygous for the T-gene mutation and had natural short-tailed parents who were heterozygous for the mutation.

The first puppy had no tail and was born alive with severe abnormalities, including light mineralization of cervical vertabral bodies, scoliosis, and kyphosis.

The second puppy (x-ray image above) had no tail and was stillborn. It had various abnormalities more severe than the first puppy did. Much of its body lacked mineralization with only four pairs of ribs attached to the spine. Its lungs were small in size and its stomach was slightly dislocated.

 

Conclusions                                                                                                                                                                   None of the studied short-tail adult corgis had any inherited spinal defects, suggesting that the mutated T-gene does not play a part in spinal abnormalities when the corgis are heterozygous for it.

Corgis homozygous for this mutation, however, suffer from extreme physical defects and cannot survive, as seen through the analysis of the two puppies. It is also likely that various combinations of alleles of genes are responsible for the numerous physical abnormalities in the puppies, although these interactions are unclear. Additionally, there have been no other reports of corgi puppies with such defects, so it can be assumed that these cases in breeding short tail x short tail are extremely low.

 

 

Indrebø, A., Langeland, M., Juul, H. M., Skogmo, H. K., Rengmark, A. H. and Lingaas, F. (2008), A study of inherited short tail and taillessness in Pembroke Welsh corgi. Journal of Small Animal Practice, 49: 220–224. doi: 10.1111/j.1748-5827.2007.00435.x