Genomic loci associated with performance limiting equine overriding spinous processes (kissing spines).

The research paper investigates “Kissing Spines” (KS) in horses, a condition affecting the spinous processes. The study examined 155 horses from various breeds, using genetic and radiological tools to grade the severity of KS. The results showed significant association with two genetic markers on chromosome 25, offering potential directions for KS diagnosis and prevention.

Subjects and Methodology

• The research involved 155 stock-type and Warmblood horses that were presented at collaborative veterinary clinics and hospitals.
• The health grade of the horses was evaluated using a clinical and radiographical phenotyping scheme, with ratings from 0 (unaffected) to 4 (severe KS).

Genetic Analysis

• The horses’ genomes were analysed using the Illumina Equine SNP70 array, a high-density genotyping platform.
• A Genome Wide Association Study (GWAS) was performed using 61,229 individual Single Nucleotide Polymorphisms (SNPs).

Findings

• Two SNPs (BIEC2-668062 and BIEC2-668013) on chromosome 25 were found to be significantly associated with the KS grade phenotype.
• This genomic segment contained about 17 coding genes and 195 ENSEMBL annotated variants.
• The SNP BIEC2-668062 significantly correlated with an increase in one KS grade per A allele in the population of horses under study.
• No significant effect was found relating to breed group, age, height, or sex in this study population.

Implications and Future Directions

• The results offer potential for future KS diagnosis and preventative measures, especially in Warmblood and stock-type breeds, which could have a higher genetic risk for more severe grades of KS.
• The researchers propose further investigation into other breeds, assessing causative variants, as well as the effect of the identified SNP (BIEC2-668062) in wider populations.