title: Bone density in sheep: genetic variation and quantitative trait loci localisation.
abstract: Bone density (BD) is an important factor in osteoporotic fracture risk in humans. However, BD is a complex trait confounded by environmental influences and polygenic inheritance. Sheep provide a potentially useful model for studying differences in BD, as they provide a means of circumventing complex environmental factors and are a similar weight to humans. The aims of this study were to establish whether there is genetic variation in BD in sheep and then to localise quantitative trait loci (QTLs) associated with this variation. We also aimed to evaluate the relationship between fat and muscle body components and BD in sheep. Results showed that there was significant (P < 0.01) genetic variation among Coopworth sheep sires for BD. This genetic difference was correlated (P < 0.01) with body weight and muscle mass. A number of QTLs exceeding the suggestive threshold were identified (nine in total). Of these, two (chromosomes 1, P < 0.05; chromosome 24, P < 0.01) were significant using genome-wide permutation significance thresholds (2000 iterations). The position of the QTL on chromosome 24 coincided with a number of other body composition QTLs, indicating possible pleiotropic effects or the presence of multiple genes affecting body composition at that site. This study shows that sheep are potentially a useful model for studying the genetics of BD.
authors.affiliation: AgResearch, Invermay Agricultural Centre, Private Bag 50034, Mosgiel, New Zealand. anna.campbell@agresearch.co.nz
authors.forename: A W
authors.initials: AW
authors.lastname: Campbell
authors.forename: W E
authors.initials: WE
authors.lastname: Bain
authors.forename: A F
authors.initials: AF
authors.lastname: McRae
authors.forename: T E
authors.initials: TE
authors.lastname: Broad
authors.forename: P D
authors.initials: PD
authors.lastname: Johnstone
authors.forename: K G
authors.initials: KG
authors.lastname: Dodds
authors.forename: B A
authors.initials: BA
authors.lastname: Veenvliet
authors.forename: G J
authors.initials: GJ
authors.lastname: Greer
authors.forename: B C
authors.initials: BC
authors.lastname: Glass
authors.forename: A E
authors.initials: AE
authors.lastname: Beattie
authors.forename: N B
authors.initials: NB
authors.lastname: Jopson
authors.forename: J C
authors.initials: JC
authors.lastname: McEwan
mesh_terms: D000818:Animals; D015519:Bone Density / Q000235:genetics*; D005260:Female; D050723:Fractures, Bone / Q000209:etiology; D014644:Genetic Variation; D006801:Humans; D008297:Male; D023421:Models, Animal; D010024:Osteoporosis / Q000150:complications / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D040641:Quantitative Trait Loci; D012756:Sheep / Q000235:genetics* / Q000378:metabolism*; D013045:Species Specificity