title: Association of low race performance with mtDNA haplogroup L3b of Australian thoroughbred horses.
abstract: Mitochondrial DNA (mtDNA) encodes the genes for respiratory chain sub-units that determine the efficiency of oxidative phosphorylation in mitochondria. The aim of this study was to determine if there were any haplogroups and variants in mtDNA that could be associated with athletic performance of Thoroughbred horses. The whole mitochondrial genomes of 53 maternally unrelated Australian Thoroughbred horses were sequenced and an association study was performed with the competition histories of 1123 horses within their maternal lineages. A horse mtDNA phylogenetic tree was constructed based on a total of 195 sequences (including 142 from previous reports). The association analysis showed that the sample groups with poor racing performance history were enriched in haplogroup L3b (p = .0003) and its sub-haplogroup L3b1a (p = .0007), while those that had elite performance appeared to be not significantly associated with haplogroups G2 and L3a1a1a (p > .05). Haplogroup L3b and L3b1a bear two and five specific variants of which variant T1458C (site 345 in 16s rRNA) is the only potential functional variant. Furthermore, secondary reconstruction of 16s RNA showed considerable differences between two types of 16s RNA molecules (with and without T1458C), indicating a potential functional effect. The results suggested that haplogroup L3b, could have a negative association with elite performance. The T1458C mutation harboured in haplogroup L3b could have a functional effect that is related to poor athletic performance.
authors.affiliation: a Tianjin Key Laboratory of Exercise Physiology and Sports Medicine , Tianjin University of Sports , Tianjin , P.R. China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Lin
authors.affiliation: b State Key Laboratory of Genetic Engineering and MOE Key Laboratory of Contemporary Anthropology, School of Life Sciences and Institutes of Biomedical Sciences , Fudan University , Shanghai , P.R.China.
authors.forename: Hong-Xiang
authors.initials: HX
authors.lastname: Zheng
authors.affiliation: c School of Health and Human Sciences , Southern Cross University , Lismore , New South Wales , Australia.
authors.forename: Allan
authors.initials: A
authors.lastname: Davie
authors.affiliation: c School of Health and Human Sciences , Southern Cross University , Lismore , New South Wales , Australia.
authors.forename: Shi
authors.initials: S
authors.lastname: Zhou
authors.affiliation: a Tianjin Key Laboratory of Exercise Physiology and Sports Medicine , Tianjin University of Sports , Tianjin , P.R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Wen
authors.affiliation: d College of Animal Sciences , Xinjiang Agricultural University , Urumuqi , China.
authors.forename: Jun
authors.initials: J
authors.lastname: Meng
authors.affiliation: a Tianjin Key Laboratory of Exercise Physiology and Sports Medicine , Tianjin University of Sports , Tianjin , P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: e Center of Systematic Genomics, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences , Urumqi , China.
authors.forename: Qimude
authors.initials: Q
authors.lastname: Aladaer
authors.affiliation: e Center of Systematic Genomics, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences , Urumqi , China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.affiliation: d College of Animal Sciences , Xinjiang Agricultural University , Urumuqi , China.
authors.forename: Wu-Jun
authors.initials: WJ
authors.lastname: Liu
authors.affiliation: d College of Animal Sciences , Xinjiang Agricultural University , Urumuqi , China.
authors.forename: Xin-Kui
authors.initials: XK
authors.lastname: Yao
mesh_terms: D000818:Animals; D001315:Australia; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D056726:Genetic Association Studies / Q000379:methods*; D006239:Haplotypes; D006736:Horses / Q000145:classification* / Q000235:genetics / Q000502:physiology; D008297:Male; D009154:Mutation; D010802:Phylogeny; D017354:Point Mutation; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D012336:RNA, Ribosomal, 16S / Q000737:chemistry / Q000235:genetics; D012420:Running; D017422:Sequence Analysis, DNA / Q000379:methods*
chemical_list: D004272:DNA, Mitochondrial; D012336:RNA, Ribosomal, 16S
keywords: Horses; athletic performance; breeding; genetics; mitochondria; mtDNA