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Does heterozygosity at the DMRT3 gene make French trotters better racers?

BACKGROUND: Recently, a mutation was discovered in the DMRT3 gene that controls pacing in horses. The mutant allele A is fixed in the American Standardbred trotter breed, while in the French trotter breed, the frequency of the wild-type allele C is still 24%. This study aimed at measuring the effect...

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Autor principal: Ricard, Anne
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4340234/
https://www.ncbi.nlm.nih.gov/pubmed/25886871
http://dx.doi.org/10.1186/s12711-015-0095-7
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author Ricard, Anne
author_facet Ricard, Anne
author_sort Ricard, Anne
collection PubMed
description BACKGROUND: Recently, a mutation was discovered in the DMRT3 gene that controls pacing in horses. The mutant allele A is fixed in the American Standardbred trotter breed, while in the French trotter breed, the frequency of the wild-type allele C is still 24%. This study aimed at measuring the effect of DMRT3 genotypes on the performance of French trotters and explaining why the polymorphism still occurs in this breed. Using a mixed animal model, genetic parameters and environmental effects on performance traits were estimated from data on 173 176 French trotter races. The effect of the DMRT3 gene was then estimated by the effect of genotype at the highly linked SNP BIEC2-620109 (C-C, A-T) for 630 horses. A selection scheme that included qualification and racing performances was modeled to (1) verify if the observed superiority of heterozygous CT horses at this SNP could be explained only by selection and (2) understand why allele C has not disappeared in French trotters. RESULTS: Heritability of racing performance traits was high for qualification test (0.56), moderate for annual earnings per finished race (0.26 to 0.31) and low for proportion of disqualified races (0.06 to 0.09). Genotype CC was always unfavorable compared to genotype TT for qualification: the probability to be qualified was 20% for CC vs. 48% for TT and earnings were -0.96 σ(y) lower for CC than for TT. Genotype CT was also unfavorable for qualification (40%) and earnings at 3 years (-0.21 σ(y)), but favorable for earnings at ages greater than 5 years: +0.41 σ(y) (P = 7.10(−4)). Selection on qualification could not explain more than 19% of the difference between genotypes CC and CT in earnings at ages greater than 5 years. Only a scenario for which genotype CT has a favorable effect on the performance of horses older than 5 years could explain that the polymorphism at the DMRT3 gene still exists in the French trotter breed. CONCLUSIONS: The use of mature horses in the French racing circuit can explain that the CA genotype is still present in the French trotter horses.
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spelling pubmed-43402342015-02-26 Does heterozygosity at the DMRT3 gene make French trotters better racers? Ricard, Anne Genet Sel Evol Research BACKGROUND: Recently, a mutation was discovered in the DMRT3 gene that controls pacing in horses. The mutant allele A is fixed in the American Standardbred trotter breed, while in the French trotter breed, the frequency of the wild-type allele C is still 24%. This study aimed at measuring the effect of DMRT3 genotypes on the performance of French trotters and explaining why the polymorphism still occurs in this breed. Using a mixed animal model, genetic parameters and environmental effects on performance traits were estimated from data on 173 176 French trotter races. The effect of the DMRT3 gene was then estimated by the effect of genotype at the highly linked SNP BIEC2-620109 (C-C, A-T) for 630 horses. A selection scheme that included qualification and racing performances was modeled to (1) verify if the observed superiority of heterozygous CT horses at this SNP could be explained only by selection and (2) understand why allele C has not disappeared in French trotters. RESULTS: Heritability of racing performance traits was high for qualification test (0.56), moderate for annual earnings per finished race (0.26 to 0.31) and low for proportion of disqualified races (0.06 to 0.09). Genotype CC was always unfavorable compared to genotype TT for qualification: the probability to be qualified was 20% for CC vs. 48% for TT and earnings were -0.96 σ(y) lower for CC than for TT. Genotype CT was also unfavorable for qualification (40%) and earnings at 3 years (-0.21 σ(y)), but favorable for earnings at ages greater than 5 years: +0.41 σ(y) (P = 7.10(−4)). Selection on qualification could not explain more than 19% of the difference between genotypes CC and CT in earnings at ages greater than 5 years. Only a scenario for which genotype CT has a favorable effect on the performance of horses older than 5 years could explain that the polymorphism at the DMRT3 gene still exists in the French trotter breed. CONCLUSIONS: The use of mature horses in the French racing circuit can explain that the CA genotype is still present in the French trotter horses. BioMed Central 2015-02-26 /pmc/articles/PMC4340234/ /pubmed/25886871 http://dx.doi.org/10.1186/s12711-015-0095-7 Text en © Ricard; licensee BioMed Central. 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Ricard, Anne
Does heterozygosity at the DMRT3 gene make French trotters better racers?
title Does heterozygosity at the DMRT3 gene make French trotters better racers?
title_full Does heterozygosity at the DMRT3 gene make French trotters better racers?
title_fullStr Does heterozygosity at the DMRT3 gene make French trotters better racers?
title_full_unstemmed Does heterozygosity at the DMRT3 gene make French trotters better racers?
title_short Does heterozygosity at the DMRT3 gene make French trotters better racers?
title_sort does heterozygosity at the dmrt3 gene make french trotters better racers?
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4340234/
https://www.ncbi.nlm.nih.gov/pubmed/25886871
http://dx.doi.org/10.1186/s12711-015-0095-7
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