Speed Index in the Racing Quarter Horse: A Genome-wide Association Study

Abstract

The racing line of Quarter Horses is characterized by great sprinting speed over short distances on straight tracks. To perform selection on racing horses, the speed index (SI) and conformation traits are often used. A genome-wide association study (GWAS) on 112 racing Quarter Horses was performed for the SI trait and markers and genes associated were reported. The GWAS was carried out using the Qxpak.5 software and the genotyping data obtained from the Equine SNP50 BeadChip. A total of eight significant SNPs (P < .0001; Qvalue of 0.25) distributed on ECA 2, 4, 10, 18 and 27 were found and served as markers for genomic regions mined for candidate genes associated with SI. For candidate gene annotation was considered 100Kb windows upstream and downstream to each important SNP. The highlighted genes were GRM8, GRIK2, NEB, ANK1 and KAT6A, since their function could be related to racing performance. Future studies should consider a validation study with an independent population and sequencing of these candidate genes should be done to identify causal alleles.

A genome-wide association study for harness racing success in the Norwegian-Swedish coldblooded trotter reveals genes for learning and energy metabolism

“…To date, significant genomic resources have been applied in studies attempting to map speed and racing success in TBs and QHs [ 4 – 18 ]. While these studies have proven to be of great value for gallop racing breeds, their applicability to harness racing breeds has been limited [ 19 – 21 ].…”

Quantitative analysis of short‐ and long‐distance racing performance in young and adult horses and association analysis with functional candidate genes in Spanish Trotter horses

“…; Meira et al . ) and metabolic pathways involving speed and endurance in horses are being studied. Moreover, the use of the strategy of MAS or directed genomic selection to improve the genetic progress of equine populations, together with the search for molecular markers associated with sporting potential, is rapidly emerging as key components of cost‐effective breeding programmes.…”

“…A range of different factors have caused these differences: the physiological status of the animal (related to the animal's level of maturity and training and their previous experiences on the track), the preselection of young horses to participate in long distances, the driver-horse interaction in the more tactical (long-distance) or faster (short-distance) races and the stricter control of the young horses in the races (compared with adults) to avoid injuries and galloping. In addition, genomewide association studies for racing performance (Schr€ oder et al 2012;Meira et al 2014) and metabolic pathways involving speed and endurance in horses are being studied. Moreover, the use of the strategy of MAS or directed genomic selection to improve the genetic progress of equine populations, together with the search for molecular markers associated with sporting potential, is rapidly emerging as key components of cost-effective breeding programmes.…”

Genomic regions associated with performance in racing line of Quarter Horses

“…Consequently, studies using only racehorses are sparse, especially those analyzing performance traits. In this respect, i.e., considering the breed as a whole, genome studies have addressed mainly population aspects (Petersen et al, 2013;Meira et al, 2014c;McCue et al, 2012), morphometric characteristics (Meira et al, 2014a), and hereditary diseases (Go et al, 2011;McQueen et al, 2014). However, some of these studies reported important, although indirect, information that could contribute to the understanding of the genetic mechanisms related to racing performance in Quarter Horses.…”