Genome-wide association study for jumping performances in French sport horses.

This research conducted a genome-wide study to identify genetic variances linked to the jumping performances of French warmblood horses, discovering a significant trait locus on chromosome 1, which accounts for 0.7% of the phenotypic variance.

Study Design and Participants

• The study involved 999 sport horses including mainly Selle Français (68%), Anglo-Arabians (13%), and horses from other European studbooks. These horses were chosen with the aim of investigating genetic factors impacting their jumping performance.

Genotyping and Quality Control

• To identify genetic differences, horses were genotyped using a tool called the Illumina EquineSNP50 BeadChip.
• Out of the 54,602 single nucleotide polymorphisms (SNPs) available on this chip, 44,424 were retained after a quality testing process which was designed to ensure the accuracy and reliability of the genetic data used in the study.

Phenotype Derivation and Models Used

• The phenotype, or observable traits, of the horses were obtained by deregressing the official breeding values for jumping competitions. This process took into account not just the performance of the individual horse but also the performances of its relatives, creating broader and more nuanced data.
• Two models were utilized to examine the effects of the genotypes on these phenotypes. These models were a single-marker mixed model and a haplotype-based mixed model. Both of these models included a polygenic effect to take familial structures into account.

Results and Conclusions

• The outcome of the study was the detection of one suggestive quantitative trait locus (QTL) situated on chromosome 1. This QTL could potentially explain up to 0.7% of the phenotypic variance in jumping performances among these horses.
• The gene RYR2, which encodes a major calcium channel in cardiac muscle in humans and mice, is located near this potential QTL – only 0.55 Megabases away. This proximity suggests a possible connection or interaction, which could form part of the basis for further exploration of the genetic factors impacting jumping ability in horses.