title: Polyceraty (multi-horns) in Damara sheep maps to ovine chromosome 2.
abstract: Polyceraty (presence of multiple horns) is rare in modern day ungulates. Although not found in wild sheep, polyceraty does occur in a small number of domestic sheep breeds covering a wide geographical region. Damara are fat-tailed hair sheep, from the south-western region of Africa, which display polyceraty, with horn number ranging from zero to four. We conducted a genome-wide association study for horn number with 43 Damara genotyped with 606 006 SNP markers. The analysis revealed a region with multiple significant SNPs on ovine chromosome 2, in a location different from the mutation for polled in sheep on chromosome 10. The causal mutation for polyceraty was not identified; however, the region associated with polyceraty spans nine HOXD genes, which are critical in embryonic development of appendages. Mutations in HOXD genes are implicated in polydactly phenotypes in mice and humans. There was no evidence for epistatic interactions contributing to polyceraty. This is the first report on the genetic mechanisms underlying polyceraty in the under-studied Damara.
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, TX, 77843, USA.
authors.forename: O F C
authors.initials: OF
authors.lastname: Greyvenstein
authors.affiliation: BioSciences Research Division, Department of Economic Developments, Jobs, Transport and Resources, 5 Ring Road, Bundoora, Vic., 3083, Australia.
authors.forename: C M
authors.initials: CM
authors.lastname: Reich
authors.affiliation: Department of Animal and Wildlife Science, University of Pretoria, Hatfield, 0028, South Africa.
authors.forename: E
authors.initials: E
authors.lastname: van Marle-Koster
authors.affiliation: Department of Animal Science, Texas A&M University, College Station, TX, 77843, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Riley
authors.affiliation: BioSciences Research Division, Department of Economic Developments, Jobs, Transport and Resources, 5 Ring Road, Bundoora, Vic., 3083, Australia.|La Trobe University, Bundoora, Vic., 3083, Australia.
authors.forename: B J
authors.initials: BJ
authors.lastname: Hayes
mesh_terms: D000818:Animals; D001947:Breeding; D002874:Chromosome Mapping; D005260:Female; D056726:Genetic Association Studies; D005819:Genetic Markers; D018398:Homeodomain Proteins / Q000235:genetics*; D006733:Horns / Q000254:growth & development*; D008297:Male; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA; D012756:Sheep / Q000235:genetics*
chemical_list: D005819:Genetic Markers; D018398:Homeodomain Proteins
keywords: GWAS; Ovine Infinium; horns; multiple horns; polycerate