The importance of the DMRT3 ‘Gait keeper’ mutation on riding traits and gaits in Standardbred and Icelandic horses

The Icelandic horse is a breed known mainly for its ability to perform the ambling four-beat gait 'tölt' and the lateral two-beat gait pace. The natural ability of the breed to perform these alternative gaits is highly desired by breeders. Therefore, the discovery that a nonsense mutation (C>A) in the DMRT3 gene was the main genetic factor for horses' ability to perform gaits in addition to walk, trot and canter was of great interest. Although several studies have demonstrated that homozygosity for the DMRT3 mutation is important for the ability to pace, only about 70% of the homozygous mutant (AA) Icelandic horses are reported to pace. The aim of the study was to genetically compare four- and five-gaited (i.e. horses with and without the ability to pace) AA Icelandic horses by performing a genome-wide association (GWA) analysis. All horses (n = 55) were genotyped on the 670K Axiom Equine Genotyping Array, and a GWA analysis was performed using the genabel package in r. No SNP demonstrated genome-wide significance, implying that the ability to pace goes beyond the presence of a single gene variant. Despite its limitations, the current study provides additional information regarding the genetic complexity of pacing ability in horses. However, to fully understand the genetic differences between four- and five-gaited AA horses, additional studies with larger sample materials and consistent phenotyping are needed.

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“…; Jäderkvist et al . ). However, only around 70% of the Icelandic horses that are homozygous mutant (AA) are reported to pace (Andersson et al .…”

Section: Top 10 Snps From the Genome‐wide Association Analysismentioning

confidence: 97%

“…; Jäderkvist et al . ). Currently, few studies have investigated the difference between horses with different gait patterns and the same DMRT3 genotype (McCoy et al .…”

Section: Top 10 Snps From the Genome‐wide Association Analysismentioning

confidence: 97%

To pace or not to pace: a pilot study of four‐ and five‐gaited Icelandic horses homozygous for the DMRT3 ‘Gait Keeper’ mutation

Fegraeus

Hirschberg

Árnason³

et al. 2017

Animal Genetics

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“…The possibility that ancient horses could rack or tölt or pace (as well as display the running walk) is an interesting find in light of recent studies in horse genetics indicating that modern horses possess a so-called "gait-keeper gene" (DMRT3) that limits the gaits and speeds of which they are capable (Andersson et al, 2012;Kristjansson et al, 2014;Promerová et al, 2014;Jäderkvist Fegraeus et al, 2015Regatieri et al, 2016). In gaited horses the DMRT3 gene has a mutation that results in a shorter and less functional protein unit.…”

Section: Scaphohippus Intermontanusmentioning

confidence: 99%

Determining the gait of Miocene, Pliocene, and Pleistocene horses from fossilized trackways

Vincelette

2021

Foss. Rec.

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Abstract. Much work has been done on the study of vertebrate gaits over the past several decades and efforts undertaken to apply this to fossil tracks, especially dinosaurs and mammals such as cats, dogs, camels, and horses. This work seeks to expand upon such studies and in particular to study footprints laid down in sand by modern horses and apply such studies to determine the gaits of fossil horse trackways. It thus builds upon the work of Renders (1984a, b) and Kienapfel et al. (2014) and suggests additional measurements that can be taken on horse footprints. In this study the footprints left in the sand by 15 horses of various breeds with various gaits were videotaped, photographed, described, and measured in order to determine characteristics useful in distinguishing gaits. These results were then applied to two new sets of fossil footprints, those of the middle Miocene merychippine horse Scaphohippus intermontanus that I personally examined and measured and those from the late Pleistocene horse Equus conversidens, previously illustrated and described in the literature (McNeil et al., 2007). The latter horse exhibits a fast gallop of around 9.4 m/s, but it is the former whose footprints are quite unique. The quantitative and visual features of these prints are suggestive of a medium-fast gait involving apparent “understepping” of diagonal couplets and hind feet that overlap the centerline. The gait that most closely matches the footprints of Scaphohippus is the “artificial” gait of a slow rack or tölt, or pace, around 1.9 m/s, though an atypical trot of a horse with major conformation issues or which is weaving (swaying) from side to side is a less likely possibility. This intimates, along with the earlier study of Renders (1984a, b), who found the artificial gait of the running walk displayed by Pliocene hipparionine horses, that ancient horses possessed a much greater variety of gaits than modern horses and that over time they lost these abilities with the exception of certain gaited breeds.

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“…In these cases, the relationship with pace was sometimes exclusive with all pacer AA and all non‐pacer CC (Novoa‐Bravo et al., 2018). However, in most breeds, there were several AA horses that were unable to pace, even if none of the CC horse were able to pace (Amano et al., 2018; Fegraeus, Hirschberg, et al., 2017; Jaderkvist et al., 2015; Kristjansson et al., 2014) or all AA horses were able to pace, and some CC horses too ( Jaderkvist, Kangas, et al., 2014). However, there has been an established relationship between genotype at DMRT3 and the ability to pace (Han & Peñagaricano, 2016).…”

Section: Discussionmentioning

confidence: 99%

“…However, there has been an established relationship between genotype at DMRT3 and the ability to pace (Han & Peñagaricano, 2016). For alternative gaits such as marcha batida, marcha picada in Brazilian Mangalarga Marchador horses (Bussiman et al., 2019, 2020; Fonseca et al., 2017; Patterson et al., 2015), rack and slow gait in American Saddlebred horses (Regatieri et al., 2016), Tölt in Icelandic horse (Fegraeus, Hirschberg, et al., 2017; Jaderkvist et al., 2015; Kristjansson et al., 2014), and Trocha and Colombian trot in Colombian horses (Novoa‐Bravo et al., 2018), the relationship with DMRT3 genotype was not so obvious and many other markers were found. We had attempted to predict the DMRT3 genotype using only the knowledge of trotting technique and failed, even if a strong difference in genotype frequency was found between main trotting technique characteristics.…”

Section: Discussionmentioning

confidence: 99%

Genomic analysis of gaits and racing performance of the French trotter

Duluard

2020

J Animal Breeding Genetics

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The aim was to disentangle gait characteristics from other qualities needed for racing performances with a genomic analysis of French trotters (FT). A sample of 1,390 horses were recruited, from which 46% were genotyped with Illumina chip of 54,602 SNPs, 49% with Affymetrix chip of 670,806 SNPs and 586 had a completed questionnaire on trotting technique. Racing performances cover the period 1996 to 2018. There were 252,368 FT‐born; 96,617 qualified and 83,962 which participated in a race. After quality control, 377,611 SNPs were retained and imputed. Questionnaire described trotting technique over 13 questions which were summarized, after principal component analysis in 3 traits: pacer, heavy trot/gallop and other defects. GWAS and genomic evaluation were performed using single‐step approach. We found 25 QTL for racing performances and 9 for trotting technique. Only DMRT3 mutation was significant for both traits. To tend to pace avoid the defect at gallop and lead to a better early career for earnings, less percentage of disqualified races at all ages and more harness than under saddle career. This is the portrait of AA genotype at DMRT3. We found 5 other QTL, not linked to gait traits, which might improve selection of genetically independent performance traits of earnings per races and percentage of finished races. For only earnings at different ages and in under saddle or harness races, genomic evaluation remains the best way to predict performances.

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The importance of the DMRT3 ‘Gait keeper’ mutation on riding traits and gaits in Standardbred and Icelandic horses

Cited by 15 publications

References 7 publications

To pace or not to pace: a pilot study of four‐ and five‐gaited Icelandic horses homozygous for the DMRT3 ‘Gait Keeper’ mutation

To pace or not to pace: a pilot study of four‐ and five‐gaited Icelandic horses homozygous for the DMRT3 ‘Gait Keeper’ mutation

Determining the gait of Miocene, Pliocene, and Pleistocene horses from fossilized trackways

Genomic analysis of gaits and racing performance of the French trotter

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