title: Association between population structure and allele frequencies of the glycogen synthase 1 mutation in the Austrian Noriker draft horse.
abstract: The aim of this study was to determine the allele frequency of the glycogen synthase 1 (GYS1) mutation associated with polysaccharide storage myopathy type 1 in the Austrian Noriker horse. Furthermore, we examined the influence of population substructures on the allele distribution. The study was based upon a comprehensive population sample (208 breeding stallions and 309 mares) and a complete cohort of unselected offspring from the year 2014 (1553 foals). The mean proportion of GYS1 carrier animals in the foal cohort was 33%, ranging from 15% to 50% according to population substructures based on coat colours. In 517 mature breeding horses the mutation carrier frequency reached 34%, ranging on a wider scale from 4% to 62% within genetic substructures. We could show that the occurrence of the mutated GYS1 allele is influenced by coat colour; genetic bottlenecks; and assortative, rotating and random mating strategies. Highest GYS1 carrier frequencies were observed in the chestnut sample comprising 50% in foals, 54% in mares and 62% in breeding stallions. The mean inbreeding of homozygous carrier animals reached 4.10%, whereas non-carrier horses were characterized by an inbreeding coefficient of 3.48%. Lowest GYS1 carrier frequencies were observed in the leopard spotted Noriker subpopulation. Here the mean carrier frequency reached 15% in foals, 17% in mares and 4% in stallions and inbreeding decreased from 3.28% in homozygous non-carrier horses to 2.70% in heterozygous horses and 0.94% in homozygous carriers. This study illustrates that lineage breeding and specified mating strategies result in genetic substructures, which affect the frequencies of the GYS1 gene mutation.
authors.affiliation: Institute of Animal Breeding and Genetics, University of Veterinary Sciences Vienna, Veterinärplatz 1, Vienna, A-1210, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Druml
authors.affiliation: Pöckau 41, A-9601, Arnoldstein, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Grilz-Seger
authors.affiliation: Agroscope, Swiss National Stud Farm, Les Longs Prés, CH-1580, Avenches, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Neuditschko
authors.affiliation: Institute of Animal Breeding and Genetics, University of Veterinary Sciences Vienna, Veterinärplatz 1, Vienna, A-1210, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Brem
mesh_terms: D000483:Alleles; D000818:Animals; D001317:Austria; D001947:Breeding; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005828:Genetics, Population; D005838:Genotype; D006006:Glycogen Synthase / Q000235:genetics*; D006200:Hair Color / Q000235:genetics*; D006579:Heterozygote; D006720:Homozygote; D006734:Horse Diseases / Q000235:genetics; D006736:Horses / Q000235:genetics*; D007178:Inbreeding; D008297:Male; D009135:Muscular Diseases / Q000235:genetics / Q000662:veterinary; D009154:Mutation; D010375:Pedigree
chemical_list: D006006:Glycogen Synthase
keywords: GYS1 gene; Noriker horse; coat colour; genetic substructures; inbreeding; polysaccharide storage myopathy