The frequency of the equine cerebellar abiotrophy mutation in non-Arabian horse breeds.

This research converse about the occurrence of the gene associated with cerebellar abiotrophy (CA), a genetic defect, in non-Arabian horse breeds. Researchers have found that those horse breeds that have historical Arabian ancestry exhibit the CA mutation.

Research Objective

• The primary aim of the study was to investigate whether the gene responsible for a genetic defect known as cerebellar abiotrophy (CA), majorly seen in Arabian horses, exist in non-Arabian horse breeds as well.
• It also aimed to find out whether the said mutation had been introduced to these breeds through Arabian ancestry.

Methods Undertaken

• A method known as Allele-specific polymerase chain reaction (PCR) was applied to genotype 1845 non-Arabian horses for the CA mutation.
• In the breeds where one or more carries were noticed, an additional 266 horses were genotyped to determine the frequency of the CA allele.
• The horses that were carriers of cerebellar abiotrophy were then subjected to further genotyping for a haplotype that segregates with CA in Arabians.

Results of the Study

• A minimum of one carrier of CA was identified in three breeds: Bashkir Curly Horses (2.8%), Trakehners (0.68%), and Welsh ponies (0.33%).
• It was concluded based on pedigree and haplotype analysis that the CA mutation was brought into these breeds via Arabian ancestry.
• The Trakehner and Welsh pony carriers were at least half-Arabian. In the case of Bashkir Curly horses, the CA allele seems to have been introduced by a single Arabian stallion that was used for developing the breed in the 1960s.

Conclusion

• The CA mutation is thus found in breeds of horses that either allow crossbreeding with Arabian horses or have used Arabian horses as foundation stock during their development.
• The study suggests that breeds which allow the registration of horses with Arabian ancestry should have any Arabian breeding stock tested for the mutation. Also, breeds descended from Arabian ancestry should pursue genetic testing of breeding stock to prevent the birth of foals affected by this genetic defect.