Genetic contributions to precocity traits in racing Thoroughbreds.
Abstract: Adaptation to early training and racing (i.e. precocity), which is highly variable in racing Thoroughbreds, has implications for the selection and training of horses. We hypothesised that precocity in Thoroughbred racehorses is heritable. Age at first sprint training session (work day), age at first race and age at best race were used as phenotypes to quantify precocity. Using high-density SNP array data, additive SNP heritability (hSNP2) was estimated to be 0.17, 0.14 and 0.17 for the three traits respectively. In genome-wide association studies (GWAS) for age at first race and age at best race, a 1.98-Mb region on equine chromosome 18 (ECA18) was identified. The most significant association was with the myostatin (MSTN) g.66493737C>T SNP (P = 5.46 × 10 and P = 1.89 × 10 respectively). In addition, two SNPs on ECA1 (g.37770220G>A and g.37770305T>C) within the first intron of the serotonin receptor gene HTR7 were significantly associated with age at first race and age at best race. Although no significant associations were identified for age at first work day, the MSTN:g.66493737C>T SNP was among the top 20 SNPs in the GWAS (P = 3.98 × 10 ). Here we have identified variants with potential roles in early adaptation to training. Although there was an overlap in genes associated with precocity and distance aptitude (i.e. MSTN), the HTR7 variants were more strongly associated with precocity than with distance. Because HTR7 is closely related to the HTR1A gene, previously implicated in tractability in young Thoroughbreds, this suggests that behavioural traits may influence precocity.
© 2017 Stichting International Foundation for Animal Genetics.
Publication Date: 2017-12-12 PubMed ID: 29230835DOI: 10.1111/age.12622Google Scholar: Lookup
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- Journal Article
Summary
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This research focuses on the investigation of the extent of genetic influence on the precociousness of racing Thoroughbreds. Various genetic variants associated with early adaptation to training and racing have been identified.
Objective and Methodology
- The researchers wanted to ascertain if precocity, or early adaptation to training and racing in racing Thoroughbreds, is an inheritable trait. Precocity has implications for selecting and training these horses.
- The age at the first sprint training session, first race, and the best race were used to quantify precocity.
- To do this, data from a high-density SNP array, a method for genotyping variations in DNA sequences, was used. The study aimed to find any significant genetic associations with these traits.
Findings
- The researchers estimated additive SNP heritability (hSNP2) to be 0.17, 0.14, and 0.17 for age at the first training session, the first race, and the best race respectively.
- Two significant genetic associations were found in genome-wide association studies (GWAS) for age at first race and age at best race. These were located in a region on equine chromosome 18 (ECA18) and were linked to the myostatin (MSTN) gene and the serotonin receptor gene HTR7 (located on ECA1).
- Although there were no significant associations found for age at first work day, the MSTN gene was among the top 20 genes in the GWAS.
Implications and Conclusions
- The results suggest a genetic basis for early adaptation to training in racing Thoroughbreds.
- While the MSTN gene was associated with both precocity and distance aptitude, HTR7 variants showed a stronger association with precocity than with distance.
- The HTR7 gene is closely related to the HTR1A gene, previously associated with tractability in young Thoroughbreds. This connection indicates that behavioural traits may influence early adaptation or precocity.
- Overall, this study highlights the potential roles of certain genes in influencing the early adaptability to training in racehorses, possibly aiding in the selection and training of these horses in the future.
Cite This Article
APA
Farries G, McGettigan PA, Gough KF, McGivney BA, MacHugh DE, Katz LM, Hill EW.
(2017).
Genetic contributions to precocity traits in racing Thoroughbreds.
Anim Genet, 49(3), 193-204.
https://doi.org/10.1111/age.12622 Publication
Researcher Affiliations
- UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland.
- UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland.
- UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland.
- UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland.
- Plusvital Ltd., Dun Laoghaire Industrial Estate, Pottery Road, Dublin, A96 KW29, Ireland.
- UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland.
- UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland.
- UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland.
- UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, D04 V1W8, Ireland.
- Plusvital Ltd., Dun Laoghaire Industrial Estate, Pottery Road, Dublin, A96 KW29, Ireland.
MeSH Terms
- Age Factors
- Animals
- Female
- Genetic Association Studies
- Genotype
- Horses / genetics
- Male
- Myostatin / genetics
- Phenotype
- Physical Conditioning, Animal
- Polymorphism, Single Nucleotide
- Receptors, Serotonin / genetics
Citations
This article has been cited 5 times.- Han H, McGivney BA, Allen L, Bai D, Corduff LR, Davaakhuu G, Davaasambuu J, Dorjgotov D, Hall TJ, Hemmings AJ, Holtby AR, Jambal T, Jargalsaikhan B, Jargalsaikhan U, Kadri NK, MacHugh DE, Pausch H, Readhead C, Warburton D, Dugarjaviin M, Hill EW. Common protein-coding variants influence the racing phenotype in galloping racehorse breeds.. Commun Biol 2022 Dec 13;5(1):1320.
- Schrurs C, Blott S, Dubois G, Van Erck-Westergren E, Gardner DS. Locomotory Profiles in Thoroughbreds: Peak Stride Length and Frequency in Training and Association with Race Outcomes.. Animals (Basel) 2022 Nov 24;12(23).
- Pira E, Vacca GM, Dettori ML, Piras G, Moro M, Paschino P, Pazzola M. Polymorphisms at Myostatin Gene (MSTN) and the Associations with Sport Performances in Anglo-Arabian Racehorses.. Animals (Basel) 2021 Mar 30;11(4).
- Han H, McGivney BA, Farries G, Katz LM, MacHugh DE, Randhawa IAS, Hill EW. Selection in Australian Thoroughbred horses acts on a locus associated with early two-year old speed.. PLoS One 2020;15(2):e0227212.
- McGivney BA, Han H, Corduff LR, Katz LM, Tozaki T, MacHugh DE, Hill EW. Genomic inbreeding trends, influential sire lines and selection in the global Thoroughbred horse population.. Sci Rep 2020 Jan 16;10(1):466.
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