The use of genomic assisted selection could allow early selection among Thoroughbreds and Polo Argentino horses for practicing polo.

This research examines the potential for using genomic markers to aid in the early selection of Polo Argentino and Thoroughbred horses, specifically for the sport of polo. The study finds that genomic differentiation in these horses could be used as a tool for future selection.

Study Background

• The research involves Polo Argentino (PA) and Thoroughbred (TB) horses, which are commonly used in the sport of polo. These breeds were developed originally by interbreeding mixed and Thoroughbred horses. However, early selection of Polo Argentino horses has been challenging due to unreliable performance estimations.

Research Method

• The study utilised the Equine GGPArray to genotype 520 Polo Argentino and 30 Thoroughbred horses identifying six genetic markers associated with behaviour, muscular development, and body size.
• These genetic markers fall within different genes known as DRD4 (connected to behaviour), MSTN (muscular development), and LCORL, HMGA2, ZFAT, and LASP1 (all associated with body size).

Findings in Genetic Differences

• The research found significant differences amongst the studied breeds regarding DRD4, MSTN, and LCORL SNP. In the last two markers, the F index (a measure of genetic variability) was found to be 0.13 and 0.6 respectively.
• In DRD4, the G allele was more prevalent in Polo Argentino horses (0.56 vs 0.45 in Thoroughbreds, although no genetic differences associated with the phenotype were observed.
• In MSTN, heterozygous genotypes were most common in Polo Argentino horses, with a significant decrease in the AA genotype, which suggests negative selection against it in polo horses.

Findings in Body Size

• When it comes to body size, HMGA2 was found to be monomorphic in all horses, meaning they all shared the same morphological trait for body size.
• On the other hand, the ZFAT and LASP1 SNP markers showed higher variability.
• Interestingly, 99% of the PA individuals revealed a TT genotype in LCORL, as opposed to only 66% in Thoroughbreds, suggesting a selection preference for smaller horses.

Conclusion

• These findings suggest that the historical selection process in Polo Argentino horses has resulted in a genomic differentiation in unique traits. This could potentially be used as a marker-assisted tool for the early selection of polo horses to improve performance in the sport.