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Sigurðardóttir H, Ablondi M, Kristjansson T, Lindgren G, Eriksson S. Genetic diversity and signatures of selection in Icelandic horses and Exmoor ponies. BMC Genomics 2024; 25:772. [PMID: 39118059 PMCID: PMC11308356 DOI: 10.1186/s12864-024-10682-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 08/01/2024] [Indexed: 08/10/2024] Open
Abstract
BACKGROUND The Icelandic horse and Exmoor pony are ancient, native breeds, adapted to harsh environmental conditions and they have both undergone severe historic bottlenecks. However, in modern days, the selection pressures on these breeds differ substantially. The aim of this study was to assess genetic diversity in both breeds through expected (HE) and observed heterozygosity (HO) and effective population size (Ne). Furthermore, we aimed to identify runs of homozygosity (ROH) to estimate and compare genomic inbreeding and signatures of selection in the breeds. RESULTS HO was estimated at 0.34 and 0.33 in the Icelandic horse and Exmoor pony, respectively, aligning closely with HE of 0.34 for both breeds. Based on genomic data, the Ne for the last generation was calculated to be 125 individuals for Icelandic horses and 42 for Exmoor ponies. Genomic inbreeding coefficient (FROH) ranged from 0.08 to 0.20 for the Icelandic horse and 0.12 to 0.27 for the Exmoor pony, with the majority of inbreeding attributed to short ROHs in both breeds. Several ROH islands associated with performance were identified in the Icelandic horse, featuring target genes such as DMRT3, DOCK8, EDNRB, SLAIN1, and NEURL1. Shared ROH islands between both breeds were linked to metabolic processes (FOXO1), body size, and the immune system (CYRIB), while private ROH islands in Exmoor ponies were associated with coat colours (ASIP, TBX3, OCA2), immune system (LYG1, LYG2), and fertility (TEX14, SPO11, ADAM20). CONCLUSIONS Evaluations of genetic diversity and inbreeding reveal insights into the evolutionary trajectories of both breeds, highlighting the consequences of population bottlenecks. While the genetic diversity in the Icelandic horse is acceptable, a critically low genetic diversity was estimated for the Exmoor pony, which requires further validation. Identified signatures of selection highlight the differences in the use of the two breeds as well as their adaptive trait similarities. The results provide insight into genomic regions under selection pressure in a gaited performance horse breed and various adaptive traits in small-sized native horse breeds. This understanding contributes to preserving genetic diversity and population health in these equine populations.
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Affiliation(s)
- Heiðrún Sigurðardóttir
- Department of Animal Biosciences, Swedish University of Agricultural Sciences, P.O. Box 7023, Uppsala, 75007, Sweden.
- Faculty of Agricultural Sciences, Agricultural University of Iceland, Hvanneyri, Borgarbyggð, 311, Iceland.
| | - Michela Ablondi
- Department of Veterinary Science, University of Parma, Parma, 43126, Italy
| | - Thorvaldur Kristjansson
- Faculty of Agricultural Sciences, Agricultural University of Iceland, Hvanneyri, Borgarbyggð, 311, Iceland
| | - Gabriella Lindgren
- Department of Animal Biosciences, Swedish University of Agricultural Sciences, P.O. Box 7023, Uppsala, 75007, Sweden
- Center for Animal Breeding and Genetics, Department of Biosystems, KU Leuven, Leuven, 3001, Belgium
| | - Susanne Eriksson
- Department of Animal Biosciences, Swedish University of Agricultural Sciences, P.O. Box 7023, Uppsala, 75007, Sweden
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Reich P, Möller S, Stock KF, Nolte W, von Depka Prondzinski M, Reents R, Kalm E, Kühn C, Thaller G, Falker-Gieske C, Tetens J. Genomic analyses of withers height and linear conformation traits in German Warmblood horses using imputed sequence-level genotypes. Genet Sel Evol 2024; 56:45. [PMID: 38872118 PMCID: PMC11177368 DOI: 10.1186/s12711-024-00914-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 05/30/2024] [Indexed: 06/15/2024] Open
Abstract
BACKGROUND Body conformation, including withers height, is a major selection criterion in horse breeding and is associated with other important traits, such as health and performance. However, little is known about the genomic background of equine conformation. Therefore, the aim of this study was to use imputed sequence-level genotypes from up to 4891 German Warmblood horses to identify genomic regions associated with withers height and linear conformation traits. Furthermore, the traits were genetically characterised and putative causal variants for withers height were detected. RESULTS A genome-wide association study (GWAS) for withers height confirmed the presence of a previously known quantitative trait locus (QTL) on Equus caballus (ECA) chromosome 3 close to the LCORL/NCAPG locus, which explained 16% of the phenotypic variance for withers height. An additional significant association signal was detected on ECA1. Further investigations of the region on ECA3 identified a few promising candidate causal variants for withers height, including a nonsense mutation in the coding sequence of the LCORL gene. The estimated heritability for withers height was 0.53 and ranged from 0 to 0.34 for the conformation traits. GWAS identified significantly associated variants for more than half of the investigated conformation traits, among which 13 showed a peak on ECA3 in the same region as withers height. Genetic parameter estimation revealed high genetic correlations between these traits and withers height for the QTL on ECA3. CONCLUSIONS The use of imputed sequence-level genotypes from a large study cohort led to the discovery of novel QTL associated with conformation traits in German Warmblood horses. The results indicate the high relevance of the QTL on ECA3 for various conformation traits, including withers height, and contribute to deciphering causal mutations for body size in horses.
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Affiliation(s)
- Paula Reich
- Department of Animal Sciences, Georg-August-University Göttingen, 37077, Göttingen, Germany.
- Center for Integrated Breeding Research (CiBreed), Georg-August-University Göttingen, 37075, Göttingen, Germany.
| | - Sandra Möller
- Department of Animal Sciences, Georg-August-University Göttingen, 37077, Göttingen, Germany
| | - Kathrin F Stock
- IT Solutions for Animal Production (vit), 27283, Verden, Germany
| | - Wietje Nolte
- Saxon State Office for Environment, Agriculture and Geology, 01468, Moritzburg, Germany
| | | | - Reinhard Reents
- IT Solutions for Animal Production (vit), 27283, Verden, Germany
| | - Ernst Kalm
- Institute of Animal Breeding and Husbandry, Kiel University, 24098, Kiel, Germany
| | - Christa Kühn
- Institute of Genome Biology, Research Institute for Farm Animal Biology (FBN), 18196, Dummerstorf, Germany
- Faculty of Agricultural and Environmental Sciences, University of Rostock, 18059, Rostock, Germany
- Friedrich-Loeffler-Institute, 17493, Greifswald - Riems Island, Germany
| | - Georg Thaller
- Institute of Animal Breeding and Husbandry, Kiel University, 24098, Kiel, Germany
| | - Clemens Falker-Gieske
- Department of Animal Sciences, Georg-August-University Göttingen, 37077, Göttingen, Germany
- Center for Integrated Breeding Research (CiBreed), Georg-August-University Göttingen, 37075, Göttingen, Germany
| | - Jens Tetens
- Department of Animal Sciences, Georg-August-University Göttingen, 37077, Göttingen, Germany
- Center for Integrated Breeding Research (CiBreed), Georg-August-University Göttingen, 37075, Göttingen, Germany
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Sigurðardóttir H, Boije H, Albertsdóttir E, Kristjansson T, Rhodin M, Lindgren G, Eriksson S. The genetics of gaits in Icelandic horses goes beyond DMRT3, with RELN and STAU2 identified as two new candidate genes. Genet Sel Evol 2023; 55:89. [PMID: 38082412 PMCID: PMC10712087 DOI: 10.1186/s12711-023-00863-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 12/01/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND In domesticated animals, many important traits are complex and regulated by a large number of genes, genetic interactions, and environmental influences. The ability of Icelandic horses to perform the gait 'pace' is largely influenced by a single mutation in the DMRT3 gene, but genetic modifiers likely exist. The aim of this study was to identify novel genetic factors that influence pacing ability and quality of the gait through a genome-wide association study (GWAS) and correlate new findings to previously identified quantitative trait loci (QTL) and mutations. RESULTS Three hundred and seventy-two Icelandic horses were genotyped with the 670 K+ Axiom Equine Genotyping Array, of which 362 had gait scores from breeding field tests. A GWAS revealed several SNPs on Equus caballus chromosomes (ECA) 4, 9, and 20 that were associated (p < 1.0 × 10-5) with the breeding field test score for pace. The two novel QTL on ECA4 and 9 were located within the RELN and STAU2 genes, respectively, which have previously been associated with locomotor behavior in mice. Haplotypes were identified and the most frequent one for each of these two QTL had a large favorable effect on pace score. The second most frequent haplotype for the RELN gene was positively correlated with scores for tölt, trot, gallop, and canter. Similarly, the second most frequent haplotype for the STAU2 gene had favorable effects on scores for trot and gallop. Different genotype ratios of the haplotypes in the RELN and STAU2 genes were also observed in groups of horses with different levels of pacing ability. Furthermore, interactions (p < 0.05) were detected for the QTL in the RELN and STAU2 genes with the DMRT3 gene. The novel QTL on ECA4, 9, and 20, along with the effects of the DMRT3 variant, were estimated to account jointly for 27.4% of the phenotypic variance of the gait pace. CONCLUSIONS Our findings provide valuable information about the genetic architecture of pace beyond the contribution of the DMRT3 gene and indicate genetic interactions that contribute to the complexity of this trait. Further investigation is needed to fully understand the underlying genetic factors and interactions.
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Affiliation(s)
- Heiðrún Sigurðardóttir
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, P.O. Box 7023, 75007, Uppsala, Sweden.
- Faculty of Agricultural Sciences, Agricultural University of Iceland, Borgarbyggð, 311, Hvanneyri, Iceland.
| | - Henrik Boije
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Elsa Albertsdóttir
- The Icelandic Agricultural Advisory Centre, Hagatorgi 1, 107, Reykjavik, Iceland
| | - Thorvaldur Kristjansson
- Faculty of Agricultural Sciences, Agricultural University of Iceland, Borgarbyggð, 311, Hvanneyri, Iceland
| | - Marie Rhodin
- Department of Anatomy, Physiology, and Biochemistry, Swedish University of Agricultural Sciences, P.O. Box 7011, 75007, Uppsala, Sweden
| | - Gabriella Lindgren
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, P.O. Box 7023, 75007, Uppsala, Sweden
- Department of Biosystems, Center for Animal Breeding and Genetics, KU Leuven, Kasteelpark Arenberg 30, 3001, Leuven, Belgium
| | - Susanne Eriksson
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, P.O. Box 7023, 75007, Uppsala, Sweden
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Dementieva N, Nikitkina E, Shcherbakov Y, Nikolaeva O, Mitrofanova O, Ryabova A, Atroshchenko M, Makhmutova O, Zaitsev A. The Genetic Diversity of Stallions of Different Breeds in Russia. Genes (Basel) 2023; 14:1511. [PMID: 37510415 PMCID: PMC10378902 DOI: 10.3390/genes14071511] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 07/17/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023] Open
Abstract
The specifics of breeding and selection significantly affect genetic diversity and variability within a breed. We present the data obtained from the genetic analysis of 21 thoroughbred and warmblood horse breeds. The most detailed information is described from the following breeds: Arabian, Trakehner, French Trotter, Standardbred, and Soviet Heavy Horse. The analysis of 509,617 SNP variants in 87 stallions from 21 populations made it possible to estimate the genetic diversity at the genome-wide level and distinguish the studied horse breeds from each other. In this study, we searched for heterozygous and homozygous ROH regions, evaluated inbreeding using FROH analysis, and generated a population structure using Admixture 1.3 software. Our findings indicate that the Arabian breed is an ancestor of many horse breeds. The study of the full-genome architectonics of breeds is of great practical importance for preserving the genetic characteristics of breeds and managing breeding. Studies were carried out to determine homozygous regions in individual breeds and search for candidate genes in these regions. Fifty-six candidate genes for the influence of selection pressure were identified. Our research reveals genetic diversity consistent with breeding directions and the breeds' history of origin.
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Affiliation(s)
- Natalia Dementieva
- Russian Research Institute of Farm Animal Genetics and Breeding-Branch of the L.K. Ernst Federal Research Center for Animal Husbandry, 55A, Moskovskoye Sh., Tyarlevo, Pushkin, St. Petersburg 196625, Russia
| | - Elena Nikitkina
- Russian Research Institute of Farm Animal Genetics and Breeding-Branch of the L.K. Ernst Federal Research Center for Animal Husbandry, 55A, Moskovskoye Sh., Tyarlevo, Pushkin, St. Petersburg 196625, Russia
| | - Yuri Shcherbakov
- Russian Research Institute of Farm Animal Genetics and Breeding-Branch of the L.K. Ernst Federal Research Center for Animal Husbandry, 55A, Moskovskoye Sh., Tyarlevo, Pushkin, St. Petersburg 196625, Russia
| | - Olga Nikolaeva
- Russian Research Institute of Farm Animal Genetics and Breeding-Branch of the L.K. Ernst Federal Research Center for Animal Husbandry, 55A, Moskovskoye Sh., Tyarlevo, Pushkin, St. Petersburg 196625, Russia
| | - Olga Mitrofanova
- Russian Research Institute of Farm Animal Genetics and Breeding-Branch of the L.K. Ernst Federal Research Center for Animal Husbandry, 55A, Moskovskoye Sh., Tyarlevo, Pushkin, St. Petersburg 196625, Russia
| | - Anna Ryabova
- Russian Research Institute of Farm Animal Genetics and Breeding-Branch of the L.K. Ernst Federal Research Center for Animal Husbandry, 55A, Moskovskoye Sh., Tyarlevo, Pushkin, St. Petersburg 196625, Russia
| | - Mikhail Atroshchenko
- All-Russian Research Institute of Horse Breeding (ARRIH), Ryazan Region, Divovo, Rybnovskij District 391105, Russia
| | - Oksana Makhmutova
- All-Russian Research Institute of Horse Breeding (ARRIH), Ryazan Region, Divovo, Rybnovskij District 391105, Russia
| | - Alexander Zaitsev
- All-Russian Research Institute of Horse Breeding (ARRIH), Ryazan Region, Divovo, Rybnovskij District 391105, Russia
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Gmel AI, Brem G, Neuditschko M. New genomic insights into the conformation of Lipizzan horses. Sci Rep 2023; 13:8990. [PMID: 37268682 DOI: 10.1038/s41598-023-36272-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/31/2023] [Indexed: 06/04/2023] Open
Abstract
Conformation traits are important selection criteria in equine breeding, as they describe the exterior aspects of the horse (height, joint angles, shape). However, the genetic architecture of conformation is not well understood, as data of these traits mainly consist of subjective evaluation scores. Here, we performed genome-wide association studies on two-dimensional shape data of Lipizzan horses. Based on this data, we identified significant quantitative trait loci (QTL) associated with cresty neck on equine chromosome (ECA)16 within the MAGI1 gene, and with type, hereby differentiating heavy from light horses on ECA5 within the POU2F1 gene. Both genes were previously described to affect growth, muscling and fatty deposits in sheep, cattle and pigs. Furthermore, we pin-pointed another suggestive QTL on ECA21, near the PTGER4 gene, associated with human ankylosing spondylitis, for shape differences in the back and pelvis (roach back vs sway back). Further differences in the shape of the back and abdomen were suggestively associated with the RYR1 gene, involved in core muscle weakness in humans. Therefore, we demonstrated that horse shape space data enhance the genomic investigations of horse conformation.
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Affiliation(s)
- A I Gmel
- Equine Department, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057, Zurich, Switzerland
- Animal GenoPhenomics, Agroscope, Rte de La Tioleyre 4, 1725, Posieux, Switzerland
| | - G Brem
- Institute of Animal Breeding and Genetics, Veterinary University Vienna, Veterinärplatz 1, 1220, Vienna, Austria
| | - M Neuditschko
- Animal GenoPhenomics, Agroscope, Rte de La Tioleyre 4, 1725, Posieux, Switzerland.
- Institute of Animal Breeding and Genetics, Veterinary University Vienna, Veterinärplatz 1, 1220, Vienna, Austria.
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Klecel W, Drobik-Czwarno W, Martyniuk E. Judging the Arabian Beauty: What are the Relationships Between Different Scoring Categories? J Equine Vet Sci 2023; 123:104247. [PMID: 36773854 DOI: 10.1016/j.jevs.2023.104247] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023]
Abstract
Arabian show horses are well known for their exceptional beauty and elegance. The breed type, body conformation and movement are assessed during horse shows by licensed judges. The 5 judging categories are type, head and neck, body and topline, legs and movement, which are scored on a 20 point scale. It can be hypothesized that the scores in different categories are related to each other, and that the score for the most subjective type category depends on the scores for conformation categories. We analyzed 762 sets of average scores obtained by 583 unique horses at the World Championships. Correlation analysis and general linear models were used to explore the relationships between the scores in each of the 5 categories. Despite the 20 point scale, only scores from 14.5 to 20 were observed. The correlations between the total score, and the scores for each category within the whole sample varied from r = 0.413 for legs to r = 0.907 for type. Regression analysis of the scores for type showed a strong, significant (P < .001) effect of the scores for the head and neck. The effect of scores for body and topline as well as for movement was negligible, while significant; the score for legs did not affect the score for type. The correlation values between score categories varied between sex and age classes. The estimated levels of correlations were different than expected, based on the known relationships between the phenotypic traits.
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Affiliation(s)
- Weronika Klecel
- Department of Animal Breeding and Conservation, Institute of Animal Sciences, Warsaw University of Life Sciences, Warsaw, Poland.
| | - Wioleta Drobik-Czwarno
- Department of Animal Breeding and Conservation, Institute of Animal Sciences, Warsaw University of Life Sciences, Warsaw, Poland
| | - Elżbieta Martyniuk
- Department of Animal Breeding and Conservation, Institute of Animal Sciences, Warsaw University of Life Sciences, Warsaw, Poland
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Gruyaert M, Pollard D, Dyson S. Relative heights of the withers and the tubera sacrale and angulation of the lumbar and pelvic regions in horses with hindlimb proximal suspensory desmopathy, sacroiliac joint region pain and other orthopaedic injuries. EQUINE VET EDUC 2022. [DOI: 10.1111/eve.13724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mounia Gruyaert
- Faculty of Veterinary Medicine, Department of Large Animal Surgery, Anaesthesia and Orthopaedics Ghent University Merelbeke Belgium
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Genetic relationship between free movement and under rider gaits in young Pura Raza Española horses. Livest Sci 2022. [DOI: 10.1016/j.livsci.2022.105031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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