A genome-wide association study for racing performances in Thoroughbreds clarifies a candidate region near the MSTN gene.

This research focused on identifying genes linked to racing performance in Thoroughbred horses, with findings highlighting a potential influence from a region near the MSTN gene.

Background and Methodology

• The researchers used a genome-wide association study (GWAS) approach, which scans the genome to find genetic variations associated with specific traits, in this case, racing performance in Thoroughbred horses.
• Performance was assessed based on lifetime earnings and racing ranks as determined by the Japan Racing Association.
• A total of 1400 genetic markers (microsatellites) were used to perform the GWAS and the racing performance trait was estimated to be 7-8% heritable (h(2)).

Results and Findings

• Through the GWAS, a significant association was found between horse performance and three specific genetic variations (SNPs) on equine chromosome 18 (ECA18).
• The three identified SNPs were g.65809482T>C, g.65868604G>T, and g.66539967A>G. These, together with a recently published nearby SNP, g.66493737C>T, all showed a very clear association with the performance.
• The region of the genome where these SNPs were identified contained eight genes annotated by ENSEMBL, including the myostatin gene (MSTN).

Conclusions

• The results indicate the presence of a gene or genes within this region on ECA18 that could significantly impact the racing performance of Thoroughbred horses. The MSTN gene, in particular, stands out as a potential candidate, though further research will be required to determine its exact role.
• This research promotes a better understanding of the genetics involved in racehorse performance, and could have practical implications for breeders and trainers in the future.