Abstract
Endurance horses are able to run at more than 20 km/h for 160 km (in bouts of 30–40 km). This level of performance is based on intense aerobic metabolism, effective body heat dissipation and the ability to endure painful exercise. The known heritabilities of endurance performance and exercise-related physiological traits in Arabian horses suggest that adaptation to extreme endurance exercise is influenced by genetic factors. The objective of the present genome-wide association study (GWAS) was to identify single nucleotide polymorphisms (SNPs) related to endurance racing performance in 597 Arabian horses. The performance traits studied were the total race distance, average race speed and finishing status (qualified, eliminated or retired). We used three mixed models that included a fixed allele or genotype effect and a random, polygenic effect. Quantile-quantile plots were acceptable, and the regression coefficients for actual vs. expected log10 p-values ranged from 0.865 to 1.055. The GWAS revealed five significant quantitative trait loci (QTL) corresponding to 6 SNPs on chromosomes 6, 1, 7, 16, and 29 (two SNPs) with corrected p-values from 1.7 × 10−6 to 1.8 × 10−5. Annotation of these 5 QTL revealed two genes: sortilin-related VPS10-domain-containing receptor 3 (SORCS3) on chromosome 1 is involved in protein trafficking, and solute carrier family 39 member 12 (SLC39A12) on chromosome 29 is active in zinc transport and cell homeostasis. These two coding genes could be involved in neuronal tissues (CNS). The other QTL on chromosomes 6, 7, and 16 may be involved in the regulation of the gene expression through non-coding RNAs, CpG islands and transcription factor binding sites. On chromosome 6, a new candidate equine long non-coding RNA (KCNQ1OT1 ortholog: opposite antisense transcript 1 of potassium voltage-gated channel subfamily Q member 1 gene) was predicted in silico and validated by RT-qPCR in primary cultures of equine myoblasts and fibroblasts. This lncRNA could be one element of the cardiac rhythm regulation. Our GWAS revealed that equine performance during endurance races is a complex polygenic trait, and is partially governed by at least 5 QTL: two coding genes involved in neuronal tissues and three other loci with many regulatory functions such as slowing down heart rate.
Highlights
A large body of epidemiological evidence suggests that regular, moderate, aerobic exercise is positively correlated with good health (Neilson et al, 2009; Bishwajit et al, 2016; Kanagasabai et al, 2017)
Three quantitative trait loci (QTL) have intronic positions in two well-conserved genes: sortilin-related VPS10domain-containing receptor 3 (SORCS3) on chromosome 1 (QTL#1), and solute carrier family 39 member 12 (SLC39A12, coding for a protein known as ZIP-12) on chromosome 29 (QTL#29)
Our genome-wide association study (GWAS) identified five significant QTL associated with the endurance performance traits in Arabian horses
Summary
A large body of epidemiological evidence suggests that regular, moderate, aerobic exercise is positively correlated with good health (Neilson et al, 2009; Bishwajit et al, 2016; Kanagasabai et al, 2017). The physiological and cellular mechanisms that underlie this correlation have not been extensively characterized. Arabian horses are well adapted to endurance racing, and are able to run at an average speed of 20 km/h or more for up to 160 km (in bouts of 30–40 km). This level of performance is based on intense aerobic metabolism, adaptation of the cardiorespiratory system, effective body heat dissipation, and maintenance of homeostasis
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have