A genome-wide scan for tying-up syndrome in Japanese Thoroughbreds.

The study conducted a detailed investigation into the genetic factors associated with ‘tying-up syndrome,’ a common muscle disorder in racehorses, specifically in Japanese Thoroughbreds.

Understanding the Syndrome and Objective of the Study

• The term ‘tying-up syndrome,’ also known as recurrent exertional rhabdomyolysis, refers to a generalized muscle disorder which is frequent among racehorses, leading to a severe impact on their performances.
• The primary objective of the study was to identify and map the candidate genomic regions related to tying-up syndrome in Japanese Thoroughbreds.

Research Methodology

• The researchers utilized a multipoint linkage analysis using LOKI, which is founded on the Bayesian Markov chain Monte Carlo method. They applied this method to five half-sib families that comprised a total of 51 affected (those with tying-up syndrome) and 277 nonaffected horses.
• They also employed a genome-wide association study (GWAS) using microsatellites on a sample size of 144 affected and 144 nonaffected horses. The main purpose of GWAS was to detect the genes associated with the disorder by analyzing the equine genome or DNA sequenced microsatellites.

Findings and Conclusion

• The linkage analysis pointed out a potent association (‘L-score’ of 82.45) between the loci UCDEQ411 and COR058 on chromosome region ECA12. The L-score indicates the likelihood of the linkage.
• The GWAS identified two potential genomic regions on ECA12 and ECA20 that may be associated with the syndrome.
• Building upon these results, the researchers concluded that the genomic region spanning UCDEQ411 and TKY499 on ECA12 showed the most significant association and was therefore proposed as a candidate region for tying-up syndrome in Japanese Thoroughbreds.

In summary, the study sheds light on possible genomic regions tied to the development of the tying-up syndrome in Japanese Thoroughbreds, providing a stepping stone towards targeted prevention strategies and potentially more effective treatments.