title: Genome-wide analysis of the world's sheep breeds reveals high levels of historic mixture and strong recent selection.
abstract: Through their domestication and subsequent selection, sheep have been adapted to thrive in a diverse range of environments. To characterise the genetic consequence of both domestication and selection, we genotyped 49,034 SNP in 2,819 animals from a diverse collection of 74 sheep breeds. We find the majority of sheep populations contain high SNP diversity and have retained an effective population size much higher than most cattle or dog breeds, suggesting domestication occurred from a broad genetic base. Extensive haplotype sharing and generally low divergence time between breeds reveal frequent genetic exchange has occurred during the development of modern breeds. A scan of the genome for selection signals revealed 31 regions containing genes for coat pigmentation, skeletal morphology, body size, growth, and reproduction. We demonstrate the strongest selection signal has occurred in response to breeding for the absence of horns. The high density map of genetic variability provides an in-depth view of the genetic history for this important livestock species.
authors.affiliation: Livestock Industries, CSIRO, Brisbane, Australia. James.Kijas@csiro.au
authors.forename: James W
authors.initials: JW
authors.lastname: Kijas
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Lenstra
authors.forename: Ben
authors.initials: B
authors.lastname: Hayes
authors.forename: Simon
authors.initials: S
authors.lastname: Boitard
authors.forename: Laercio R
authors.initials: LR
authors.lastname: Porto Neto
authors.forename: Magali
authors.initials: M
authors.lastname: San Cristobal
authors.forename: Bertrand
authors.initials: B
authors.lastname: Servin
authors.forename: Russell
authors.initials: R
authors.lastname: McCulloch
authors.forename: Vicki
authors.initials: V
authors.lastname: Whan
authors.forename: Kimberly
authors.initials: K
authors.lastname: Gietzen
authors.forename: Samuel
authors.initials: S
authors.lastname: Paiva
authors.forename: William
authors.initials: W
authors.lastname: Barendse
authors.forename: Elena
authors.initials: E
authors.lastname: Ciani
authors.forename: Herman
authors.initials: H
authors.lastname: Raadsma
authors.forename: John
authors.initials: J
authors.lastname: McEwan
authors.forename: Brian
authors.initials: B
authors.lastname: Dalrymple
mesh_terms: D000349:Africa; D000818:Animals; D001208:Asia; D005060:Europe; D005787:Gene Frequency; D016678:Genome; D008957:Models, Genetic; D010802:Phylogeny; D058974:Phylogeography; D020641:Polymorphism, Single Nucleotide; D025341:Principal Component Analysis; D012641:Selection, Genetic; D012756:Sheep / Q000235:genetics*