title: Peeling back the evolutionary layers of molecular mechanisms responsive to exercise-stress in the skeletal muscle of the racing horse.
abstract: The modern horse (Equus caballus) is the product of over 50 million yrs of evolution. The athletic abilities of the horse have been enhanced during the past 6000 yrs under domestication. Therefore, the horse serves as a valuable model to understand the physiology and molecular mechanisms of adaptive responses to exercise. The structure and function of skeletal muscle show remarkable plasticity to the physical and metabolic challenges following exercise. Here, we reveal an evolutionary layer of responsiveness to exercise-stress in the skeletal muscle of the racing horse. We analysed differentially expressed genes and their co-expression networks in a large-scale RNA-sequence dataset comparing expression before and after exercise. By estimating genome-wide dN/dS ratios using six mammalian genomes, and FST and iHS using re-sequencing data derived from 20 horses, we were able to peel back the evolutionary layers of adaptations to exercise-stress in the horse. We found that the oldest and thickest layer (dN/dS) consists of system-wide tissue and organ adaptations. We further find that, during the period of horse domestication, the older layer (FST) is mainly responsible for adaptations to inflammation and energy metabolism, and the most recent layer (iHS) for neurological system process, cell adhesion, and proteolysis.
authors.affiliation: Department of Agricultural Biotechnology, Animal Biotechnology Major, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Hyeongmin
authors.initials: H
authors.lastname: Kim
authors.forename: Taeheon
authors.initials: T
authors.lastname: Lee
authors.forename: Woncheoul
authors.initials: W
authors.lastname: Park
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: Jaemin
authors.initials: J
authors.lastname: Kim
authors.forename: Bo-Young
authors.initials: BY
authors.lastname: Lee
authors.forename: Hyeonju
authors.initials: H
authors.lastname: Ahn
authors.forename: Sunjin
authors.initials: S
authors.lastname: Moon
authors.forename: Seoae
authors.initials: S
authors.lastname: Cho
authors.forename: Kyoung-Tag
authors.initials: KT
authors.lastname: Do
authors.forename: Heui-Soo
authors.initials: HS
authors.lastname: Kim
authors.forename: Hak-Kyo
authors.initials: HK
authors.lastname: Lee
authors.forename: Chang-Kyu
authors.initials: CK
authors.lastname: Lee
authors.forename: Hong-Sik
authors.initials: HS
authors.lastname: Kong
authors.forename: Young-Mok
authors.initials: YM
authors.lastname: Yang
authors.forename: Jongsun
authors.initials: J
authors.lastname: Park
authors.forename: Hak-Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Kim
authors.forename: Seungwoo
authors.initials: S
authors.lastname: Hwang
authors.forename: Jong
authors.initials: J
authors.lastname: Bhak
authors.forename: Dave
authors.initials: D
authors.lastname: Burt
authors.forename: Kyoung-Do
authors.initials: KD
authors.lastname: Park
authors.forename: Byung-Wook
authors.initials: BW
authors.lastname: Cho
authors.forename: Heebal
authors.initials: H
authors.lastname: Kim
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000818:Animals; D017849:Animals, Inbred Strains; D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D016678:Genome; D006736:Horses / Q000235:genetics*; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000502:physiology; D005082:Physical Exertion / Q000235:genetics*; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger
keywords: RNA sequencing; evolution; exercise; horse; re-sequencing