title: Population Variation Reveals Independent Selection toward Small Body Size in Chinese Debao Pony.
abstract: Body size, one of the most important quantitative traits under evolutionary scrutiny, varies considerably among species and among populations within species. Revealing the genetic basis underlying this variation is very important, particularly in humans where there is a close relationship with diseases and in domestic animals as the selective patterns are associated with improvements in production traits. The Debao pony is a horse breed with small body size that is unique to China; however, it is unknown whether the size-related candidate genes identified in Western breeds also account for the small body size of the Debao pony. Here, we compared individual horses from the Debao population with other two Chinese horse populations using single nucleotide polymorphisms (SNPs) identified with the Equine SNP 65 Bead Chip. The previously reported size-related candidate gene HMGA2 showed a significant signature for selection, consistent with its role observed in human populations. More interestingly, we found a candidate gene TBX3, which had not been observed in previous studies on horse body size that displayed the highest differentiation and most significant association, and thus likely is the dominating factor for the small stature of the Debao pony. Further comparison between the Debao pony and other breeds of horses from around the world demonstrated that TBX3 was selected independently in the Debao pony, suggesting that there were multiple origins of small stature in the horse.
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Adiljan
authors.initials: A
authors.lastname: Kader
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Kunzhe
authors.initials: K
authors.lastname: Dong
authors.affiliation: Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: David M
authors.initials: DM
authors.lastname: Irwin
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Qianjun
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: He
authors.affiliation: College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Liu
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yabin
authors.initials: Y
authors.lastname: Pu
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Neena Amatya
authors.initials: NA
authors.lastname: Gorkhali
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Xuexue
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Xiangchen
authors.initials: X
authors.lastname: Li
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Weijun
authors.initials: W
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China wudongdong@mail.kiz.ac.cn mayuehui@caas.cn.
authors.forename: Dong-Dong
authors.initials: DD
authors.lastname: Wu
authors.affiliation: Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China wudongdong@mail.kiz.ac.cn mayuehui@caas.cn.
authors.forename: Yuehui
authors.initials: Y
authors.lastname: Ma
mesh_terms: D000818:Animals; D049628:Body Size / Q000235:genetics*; D025743:HMGA2 Protein / Q000235:genetics; D006736:Horses / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic; D020825:T-Box Domain Proteins / Q000235:genetics
chemical_list: D025743:HMGA2 Protein; D020825:T-Box Domain Proteins
keywords: TBX3; XP-EHH; association; di; genetic differentiation; selective signature