From Drug Doping to Gene Doping in Horse

Document Type : Research Paper

Authors

1 Ph.D. Student, Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran

2 Assistant Professor, Department of Animal Science, Faculty of Agriculture, University of Zanjan, Zanjan, Iran

Abstract

Objective
According to the World Anti-Doping Agency (WADA), gene doping refers to the non-therapeutic use of genes, gene components, and cellular elements that enhance the athletic performance capacity of animals. Doping used to be done with various drugs such as Anabolic Androgenic Steroids (AAS), Caffeine, Cocaine, Amphetamine, Apomorphine, Fentanyl, Barbiturates, Butazone, etc. but with the progress in the field of gene therapy, the necessary tools for gene doping were created. The objectives of this review were to introduce the types of drug doping, gene doping, the detection methods and important candidate genes used in gene doping in horses.
Gene Doping Methods and Detection Techniques
Gene doping methods can generally be classified into three categories: gene transfer, gene silencing, and gene editing. Various methods have been proposed for detecting gene doping, which can be broadly categorized as indirect and direct detection methods. Indirect methods measure the body's responses to doping, while direct method, which clearly identifies the doping agent, the goal is to identify the genetic materials of doping, a protein produced from the gene doping gene, or a vector. All gene doping detection methods have their advantages and disadvantages, and it is evident that detecting gene doping will be challenging.
Candidate Genes in Gene Doping
Candidate genes commonly used in gene doping include EPO, IGF1, GH, HIF1, PPARD, MSTN, ACTN2, ACTN3, VEGFA, POMC, PENK, ACE, and PCK1.
Conclusion
Given the sensitivity and significance of equestrian sports and horse racing, the likelihood of owners, trainers, and riders resorting to doping to achieve victory is increasing. As gene doping is more effective and harder to detect than traditional drug doping, it receives more attention from offenders. As a result, equestrian and horse racing competitions are facing a new challenge known as gene doping. Although there is currently no evidence of gene doping being used, the necessary technology exists to implement various forms of gene doping. The most effective measure for controlling doping is the introduction of precise doping detection tests. While a wide range of diagnostic tests has been proposed, there is currently no official and widespread method for detecting gene doping. A successful anti-doping program should not only include diagnostic tests but also focus on education, supervision, and implementation methods.

Keywords


اسدالله پور نعنایی حجت، نصرتی مریم، محمدآبادی محمدرضا (1400). بررسی ساختار ژنتیکی جمعیت اسب آخال-تکه و مقایسه آن با نژادهای دیگر با استفاده از داده های تعیین توالی کل ژنوم. فصلنامه ژنتیک نوین 16(4)، 307-299.
وزیری ماندانا، سارانی علی، جهانتیغ مهدی (1394). تشخیص سریع و بررسی برخی از مارکرهای استرس‌اکسیداتیو ناشی از دوپینگ با مورفین در اسب. پایان نامه دکتری، دانشگاه زابل، 5-4.
References
Ahmetov II, Mozhayskaya IA, Flavell DM et al. (2006) PPARα gene variation and physical performance in Russian athletes. Eur J Appl Physiol 97, 103-108.
Asahara T, Bauters C, Zheng LP et al. (1995) Synergistic effect of vascular endothelial growth factor and basic fibroblast growth factor on angiogenesis in vivo. Circ 92, 365-371.
Asadollahpour HN, Nosrati M, Mohammadabadi MR (2021) Genetic structure analysis of Akhal-Teke horse population and comparison with other horse breeds by using whole genome sequencing data. Modern Genet 16, 299-307 (In Persian).
Azzazy HME, Mansour MMH, Christenson RH (2005) Doping in the recombinant era: strategies and counterstrategies. Clin Biochem 38(11), 959-965.
Azzazy HME, Mansour MMH, Christenson RH (2009) Gene doping: of mice and men. Clin Biochem 42(6), 435-441.
Bailly-Chouriberry L, Pinel G, Garcia P et al. (2008) Identification of recombinant equine growth hormone in horse plasma by LC− MS/MS: a confirmatory analysis in doping control. Anal Chem 80(21), 8340-8347.
Bailly‐Chouriberry L, Noguier F, Manchon L et al. (2010) Blood cells RNA biomarkers as a first long‐term detection strategy for EPO abuse in horseracing. Drug Test Anal 2(7), 339-345.
Baoutina A, Alexander IE, Rasko JEJ et al. (2007) Potential use of gene transfer in athletic performance enhancement. Mol Ther 15(10), 1751-1766.
Baoutina A, Alexander IE, Rasko JEJ et al. (2008) Developing strategies for detection of gene doping. J Gene Med 10(1), 3-20.
Baoutina A, Coldham T, Bains GS et al. (2010) Gene doping detection: evaluation of approach for direct detection of gene transfer using erythropoietin as a model system. Gene Ther 17(8), 1022-1032.
Baoutina A, Coldham T, Fuller B et al. (2013) Improved detection of transgene and nonviral vectors in blood. Hum Gene Ther Methods 24(6), 345-354.
Barragry TB (1994) Veterinary drug therapy, Lea & Febiger, Philadelphia. pp. 189-193
Barry P (2008) Finding the golden genes: Advances in gene therapy could tempt some athletes to enhance their genetic makeup, leading some researchers to work on detection methods just in case. Sci News 174(3), 16-21.
Barton-Davis ER, Shoturma DI, Musaro A et al. (1998) Viral mediated expression of insulin-like growth factor I blocks the aging-related loss of skeletal muscle function. Proc Natl Acad Sci 95(26), 15603-15607.
Barton ER, Morris L, Musaro A et al. (2002) Muscle-specific expression of insulin-like growth factor I counters muscle decline in mdx mice. J Cell Biol 157(1), 137-148.
Bayarsaikhan O, Kawai N, Mori H et al. (2017) Co-administration of myostatin-targeting siRNA and ActRIIB-Fc fusion protein increases masseter muscle mass and fiber size. J Nutr Sci Vitaminol 63(4), 244-248.
Berggren A, Ehrnborg C, Rosén T et al. (2005) Short-term administration of supraphysiological recombinant human growth hormone (GH) does not increase maximum endurance exercise capacity in healthy, active young men and women with normal GH-insulin-like growth factor I axes. J Clin Endocrinol Meta 90(6), 3268-3273.
Birzniece V, Nelson AE, Ho KKY (2011) Growth hormone and physical performance. Trends Endocrinol Metab 22(5), 171-178.
Booth FW, Thomason DB (1991) Molecular and cellular adaptation of muscle in response to exercise: perspectives of various models. Physiol Rev 71(2), 541-585.
Bosch G, van Schie HTM, de Groot MW et al. (2010) Effects of platelet‐rich plasma on the quality of repair of mechanically induced core lesions in equine superficial digital flexor tendons: a placebo‐controlled experimental study. J Orthop Res 28(2), 211-217.
Brüning JC, Michael MD, Winnay JN et al. (1998) A muscle-specific insulin receptor knockout exhibits features of the metabolic syndrome of NIDDM without altering glucose tolerance. Mol Cell 2(5), 559-569.
Chong ZZ, Kang J-Q, Maiese K (2002) Angiogenesis and plasticity: role of erythropoietin in vascular systems. J Hematother Stem Cell Res 11(6), 863-871.
Clop A, Marcq F, Takeda H et al. (2006) A mutation creating a potential illegitimate microRNA target site in the myostatin gene affects muscularity in sheep. Nat Genet 38(7), 813-818.
Connaughton S, Chowdhury F, Attia RR et al. (2010) Regulation of pyruvate dehydrogenase kinase isoform 4 (PDK4) gene expression by glucocorticoids and insulin. Mol Cell Endocrinol 315(1-2), 159-167.
Cooper C, Sears W, Bienzle D (2005) Reticulocyte changes after experimental anemia and erythropoietin treatment of horses. J Appl Physio 99(3), 915-921.
Creaney L, Hamilton B (2008) Growth factor delivery methods in the management of sports injuries: the state of play. Br J Sports Med 42(5), 314-320.
de Kock SS, Rodgers JP, Swanepoel BC (2001) Growth hormone abuse in the horse: preliminary assessment of a mass spectrometric procedure for IGF‐1 identification and quantitation. Rapid Commun Mass Sp 15(14), 1191-1197.
Déry M-AC, Michaud MD, Richard DE (2005) Hypoxia-inducible factor 1: regulation by hypoxic and non-hypoxic activators. Int J Biochem Cell Biol 37(3), 535-540.
Deventer K, Roels K, Delbeke FT et al. (2011) Prevalence of legal and illegal stimulating agents in sports. Anal Bioanal Chem 401, 421-432.
Doukas J, Blease K, Craig D et al. (2002) Delivery of FGF genes to wound repair cells enhances arteriogenesis and myogenesis in skeletal muscle. Mol Ther 5(5), 517-527.
Echegaray M, Rivera MA (2001) Role of creatine kinase isoenzymes on muscular and cardiorespiratory endurance: genetic and molecular evidence. Sports Med 31, 919-934.
Egan B, Zierath JR (2013) Exercise metabolism and the molecular regulation of skeletal muscle adaptation. Cell Metabol 17(2), 162-184.
Eivers SS, McGivney BA, Fonseca RG et al. (2010) Alterations in oxidative gene expression in equine skeletal muscle following exercise and training. Physiol Genomics 40(2), 83-93.
Eivers SS, McGivney BA, Gu J et al. (2012) PGC‐1α encoded by the PPARGC1A gene regulates oxidative energy metabolism in equine skeletal muscle during exercise. Anim Genet 43(2), 153-162.
Eynon N, Meckel Y, Sagiv M et al. (2010) Do PPARGC1A and PPARα polymorphisms influence sprint or endurance phenotypes?. Scand J Med Sci Sports 20(1), e145-e150.
Fisher JW (2003) Erythropoietin: physiology and pharmacology update. Exp Biol Med 228(1), 1-14.
Gaffney B, Cunningham EP (1988) Estimation of genetic trend in racing performance of thoroughbred horses. Nature 332(6166), 722-724.
Gianola D, Simianer H (2006) A Thurstonian Model for Quantitative Genetic Analysis of Ranks: A Bayesian Approach. Genet, 174(3), 1613-1624.
Gibney J, Healy M-L, Sönksen PH (2007) The growth hormone/insulin-like growth factor-I axis in exercise and sport. Endocr Rev 28(6), 603-624.
Glass DJ (2010) IGF-1 Regulation of Skeletal Muscle Hypertrophy and Atrophy. In:  IGFs:Local Repair and Survival Factors Throughout Life Span. Clemmons D, Robinson I, Christen Y (eds) Springer, Berlin. pp. 85–96.
Goins WF, Cohen JB, Glorioso JC (2012) Gene therapy for the treatment of chronic peripheral nervous system pain. Neurobiol Dis 48(2), 255-270.
Gould D (2013) Gene doping: gene delivery for olympic victory. Br J Clin Pharmacol 76(2), 292-298.
Gu J, MacHugh DE, McGivney BA et al. (2010) Association of sequence variants in CKM (creatine kinase, muscle) and COX4I2 (cytochrome c oxidase, subunit 4, isoform 2) genes with racing performance in Thoroughbred horses. Equine Vet J 42, 569-575.
Guan F, Uboh CE, Soma LR et al. (2007) LC-MS/MS method for confirmation of recombinant human erythropoietin and darbepoetin α in equine plasma. Anal Chem 79(12), 4627-4635.
Guest NS, VanDusseldorp TA, Nelson MT et al. (2021) International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr 18(1), 1.
Gustafsson T (2011) Vascular remodelling in human skeletal muscle. Biochem Soc Trans 39(6), 1628-1632.
Haidet AM, Rizo L, Handy C et al. (2008) Long-term enhancement of skeletal muscle mass and strength by single gene administration of myostatin inhibitors. Proc Natl Acad Sci 105(11), 4318-4322.
Haisma HJ, de Hon O (2006) Gene doping. Int J Sports Med 27(04), 257-266.
Hill EW, Eivers SS, McGivney BA et al. (2010a) Moderate and high intensity sprint exercise induce differential responses in COX4I2 and PDK4 gene expression in Thoroughbred horse skeletal muscle. Equine Vet J 42, 576-581.
Hill EW, Gu J, Eivers SS et al. (2010b) A sequence polymorphism in MSTN predicts sprinting ability and racing stamina in thoroughbred horses. PLoS One 5(1), e8645.
Hill EW, Gu J, McGivney BA et al. (2010c) Targets of selection in the Thoroughbred genome contain exercise‐relevant gene SNPs associated with elite racecourse performance. Anim Genet 41, 56-63.
Hirsch ML, Wolf SJ, Samulski RJ (2016) Delivering transgenic DNA exceeding the carrying capacity of AAV vectors. Gene Therapy for Neurological Disorders: Methods and Protocols 21-39.
Howley ET, Bassett DR, Welch HG (1995) Criteria for maximal oxygen uptake: review and commentary. Med Sci Sports Exerc 27(9), 1292-1301.
IFHA IFoHA (2022) International Federation of Horseracing Authorities. Article 6 of the International Agreement on Breeding, Racing and Wagering. pp. 1-110.
Jeoung NH, Harris RA (2010) Role of pyruvate dehydrogenase kinase 4 in regulation of blood glucose levels. Korean Diabetes J 34(5), 274-283.
Jinek M, Chylinski K, Fonfara I et al. (2012) A programmable dual-RNA–guided DNA endonuclease in adaptive bacterial immunity. Sci 337(6096), 816-821.
Jonse WE (1989) Equine sport medicine, Lea & Febiger, Philadelphia. pp. 138-145.
Kearns CF, McKeever KH, Abe T (2002) Overview of horse body composition and muscle architecture: implications for performance. Vet J 164(3), 224-234.
Khan T, Weber H, DiMuzio J et al. (2016) Silencing myostatin using cholesterol-conjugated siRNAs induces muscle growth. Mol Ther Nucleic Acids 5.
King EJ (1999) Performance of AdultaCheck 4 test strips for the detection of adulteration at the point of collection of urine specimens used for drugs-of-abuse testing. J Anal Toxicol 23(1), 72-72.
Koneru A, Satyanarayana S, Rizwan S (2009) Endogenous opioids: their physiological role and receptors. Glob J Pharmacol 3(3), 149-153.
Kosicki M, Tomberg K, Bradley A (2018) Repair of double-strand breaks induced by CRISPR–Cas9 leads to large deletions and complex rearrangements. Nat Biotechnol 36(8), 765-771.
Kota J, Handy CR, Haidet AM et al. (2009) Follistatin gene delivery enhances muscle growth and strength in nonhuman primates. Sci Transl Med 1(6), 6ra15-6ra15.
Langley B, Thomas M, Bishop A et al. (2002) Myostatin inhibits myoblast differentiation by down-regulating MyoD expression. J Biol Chem 277(51), 49831-49840.
Lasne F, Popot M-A, Varlet-Marie E et al. (2005) Detection of recombinant epoetin and darbepoetin alpha after subcutaneous administration in the horse. J Anal Toxicol 29(8), 835-837.
Lee C-H, Olson P, Evans RM (2003) Minireview: lipid metabolism, metabolic diseases, and peroxisome proliferator-activated receptors. Endocrinol 144(6), 2201-2207.
Lee S-J, McPherron AC (2001) Regulation of myostatin activity and muscle growth. Proc Natl Acad Sci 98(16), 9306-9311.
Lee S, Barton ER, Sweeney HL et al. (2004) Viral expression of insulin-like growth factor-I enhances muscle hypertrophy in resistance-trained rats. J Appl Physiol 96(3), 1097-1104.
Lino CA, Harper JC, Carney JP et al. (2018) Delivering CRISPR: a review of the challenges and approaches. Drug Deliv 25(1), 1234-1257.
Macdougall IC, Ashenden M (2009) Current and upcoming erythropoiesis-stimulating agents, iron products, and other novel anemia medications. Adv Chronic Kidney Dis 16(2), 117-130.
Martier R, Liefhebber JM, García-Osta A et al. (2019) Targeting RNA-mediated toxicity in C9orf72 ALS and/or FTD by RNAi-based gene therapy. Mol Ther Nucleic Acids 16, 26-37.
Mata X, Vaiman A, Ducasse A et al. (2012) Genomic structure, polymorphism and expression of the horse alpha-actinin-3 gene. Gene 491(1), 20-24.
McKeever KH, Agans JM, Geiser S et al. (2006) Low dose exogenous erythropoietin elicits an ergogenic effect in standardbred horses. Equine Vet J 38(S36), 233-238.
McKeever KH, Arent SM, Davitt P (2013) Endocrine and Immune Responses to Exercise. The Athletic Horse: Principles and Practice of Equine Sports Medicine, 88-107.
McMiken DF (1983) An energetic basis of equine performance. Equine Vet J 15(2), 123-133.
McPherron AC, Lee S-J (2002) Suppression of body fat accumulation in myostatin-deficient mice. J Clin Investig, 109(5), 595-601.
Mendell JR, Sahenk Z, Malik V et al. (2015) A phase 1/2a follistatin gene therapy trial for becker muscular dystrophy. Mol Ther 23(1), 192-201.
Moazemi I, Mohammadabadi MR, Mostafavi A, Esmailizadeh AK, Babenko OI, Bushtruk MV, Tkachenko SV, Stavetska RV, Klopenko NI. Polymorphism of DMRT3 Gene and Its Association with Body Measurements in Horse Breeds. Russ J Genet 56, 1232-1240.
Mobasheri A, Proudman CJ (2015) Cobalt chloride doping in racehorses: Concerns over a potentially lethal practice. Vet J 205(3), 335-338.
Moro LN, Viale DL, Bastón JI et al. (2020) Generation of myostatin edited horse embryos using CRISPR/Cas9 technology and somatic cell nuclear transfer. Sci Rep 10(1), 15587.
Mosher DS, Quignon P, Bustamante CD et al. (2007) A mutation in the myostatin gene increases muscle mass and enhances racing performance in heterozygote dogs. PLoS Genet 3(5), e79.
Mosler S, Geisler S, Hengevoss J et al. (2013) Modulation of follistatin and myostatin propeptide by anabolic steroids and gender. Int J Sports Med 34(07), 567-572.
Mostafavi A, Fozi MA, Koshkooieh AE, Mohammadabadi M, Babenko OI, Klopenko NI. Effect of LCORL gene polymorphism on body size traits in horse populations. Acta Sci. - Anim Sci 42.
Muchnik E, Kaplan J (2011) HIF prolyl hydroxylase inhibitors for anemia. Expert Opin Drug Discov 20(5), 645-656.
Nagel H (2013) The Arabian Horse: Nature's Creation and the Art of Breeding. Nawal media.
Neto LMR, Andraus MH, Salvadori MC (1996) Determination of phenylbutazone and oxyphenbutazone in plasma and urine samples of horses by high-performance liquid chromatography and gas chromatography-mass spectrometry. J Chromatogr B Biomed Appl 678(2), 211-218.
Noh MJ CO, O’Mara M, Lee KH (2015) Cell mediated gene therapy: A guide for doctors in the clinic. World J Med Genet 5(1), 1-13.
North KN (2010) Actn3 genotype screen for athletic performance. Google Patents.
Olsson B, Alberg L, Cullen NC et al. (2019) NFL is a marker of treatment response in children with SMA treated with nusinersen. J Neurol 266, 2129-2136.
Ornitz DM, Itoh N (2001) Fibroblast growth factors. Genome Biol 2(3), 1-12.
Pereira GL, de Matteis R, Meira CT et al. (2016) Comparison of sequence variants in the PDK4 and COX4I2 genes between racing and cutting lines of quarter horses and associations with the speed index. J Vet Sci 39, 1-6.
Petersen JL, Mickelson JR, Cothran EG et al. (2013) Genetic Diversity in the Modern Horse Illustrated from Genome-Wide SNP Data. PloS one 8(1), e54997.
Pradhan A, Kalin TV, Kalinichenko VV (2020) Genome editing for rare diseases. Curr Stem Cell Rep 6, 41-51.
Regatieri IC, Pereira GL, Neto ART et al. (2017) Polymorphisms in MCT1, CD147, PDK4, and DMRT3 genes in Arabian and Quarter Horses. J Vet Sci 48, 161-165.
Russell AP, Feilchenfeldt J, Schreiber S et al. (2003) Endurance training in humans leads to fiber type-specific increases in levels of peroxisome proliferator-activated receptor-γ coactivator-1 and peroxisome proliferator-activated receptor-α in skeletal muscle. Diabetes 52(12), 2874-2881.
Sanchez LC, Robertson SA (2014) Pain control in horses: what do we really know?. Equine Vet J 46(4), 517-523.
SanGiacomo N, Brooks S (2013) The impact of myostatin genetic polymorphism on muscle conformation in the horse. PhD thesis, University of Cornell. pp. 4-13.
Santagostino M, Khoriauli L, Gamba R et al. (2015) Genome-wide evolutionary and functional analysis of the Equine Repetitive Element 1: an insertion in the myostatin promoter affects gene expression. BMC Genet 16(1), 1-16.
Sato F, Yamashita S, Kugo T et al. (2004) Nucleotide sequence of equine erythropoietin and characterization of region-specific antibodies. Am J Vet Res 65(1), 15-19.
Schneider AJ, Friedmann T (2006) The problem of doping in sports. Adv Genet 51, 1-9.
Schröder W, Klostermann A, Distl O (2011) Candidate genes for physical performance in the horse. Vet J 190(1), 39-48.
Schuelke M, Wagner KR, Stolz LE et al. (2004) Myostatin mutation associated with gross muscle hypertrophy in a child. N Engl J Med, 350(26), 2682-2688.
Seto JT, Quinlan KGR, Lek M et al. (2013) ACTN3 genotype influences muscle performance through the regulation of calcineurin signaling. J Clin Investig 123(10), 4255-4263.
Soares A, Guimarães S, Kelly M et al. (2017) Multiple-trait genomewide mapping and gene network analysis for scrotal circumference growth curves in Brahman cattle. J Anim Sci 95, 3331-3345.
Sottas P-E, Robinson N, Rabin O et al. (2011) The athlete biological passport. Clin Chem 57(7), 969-976.
Stephan BC, Parsa FD (2016) Avoiding opioids and their harmful side effects in the postoperative patient: exogenous opioids, endogenous endorphins, wellness, mood, and their relation to postoperative pain. Hawaii J Med Public Health 75(3), 63.
Teale P, Scarth J, Hudson S (2012) Impact of the emergence of designer drugs upon sports doping testing. Bioanal 4(1), 71-88.
Thomas KC, Hamilton NA, North KN et al. (2014) Sequence analysis of the equine ACTN3 gene in Australian horse breeds. Gene 538(1), 88-93.
Thorpe CT, Clegg PD, Birch HL (2010) A review of tendon injury: why is the equine superficial digital flexor tendon most at risk?.  Equine Vet J 42(2), 174-180.
Tobin T (1981) Drugs and the performance horse, Charles C. Thomas, USA. pp. 185-190.
Tozaki T, Hamilton NA (2022) Control of gene doping in human and horse sports. Gene Ther 29(3-4), 107-112.
Tozaki T, Sato F, Hill EW et al. (2011) Sequence variants at the myostatin gene locus influence the body composition of Thoroughbred horses. J Vet Med Sci 73(12), 1617-1624.
Tural E, Kara N, Agaoglu SA et al. (2014) PPAR-α and PPARGC1A gene variants have strong effects on aerobic performance of Turkish elite endurance athletes. Mol Biol Rep 41, 5799-5804.
Valberg S, ESSÉN‐GUSTAVSSON B, Lindholm A et al. (1985) Energy metabolism in relation to skeletal muscle fibre properties during treadmill exercise. Equine Vet J 17(6), 439-444.
van der Gronde T, de Hon O, Haisma HJ et al. (2013) Gene doping: an overview and current implications for athletes. Br J Sports Med 47(11), 670-678.
Vaziri M, Sarani A, Jahantigh M (2015) Rapid detection of doping with morphine and study of some oxidative stres markers due to morphine in horses. PhD thesis, University of zabol. pp. 4-5. (In Persian)
Verardo LL, Silva FF, Lopes MS et al. (2016) Revealing new candidate genes for reproductive traits in pigs: combining Bayesian GWAS and functional pathways. Genet Sel Evol 48, 1-13.
WADA (2023) International standard prohibited list. pp. 1-24.
WADA (2021) International standard for testing and investigations.
WAHO (2020) WAHO General News.
Wallimann T, Hemmer W (1994) Creatine kinase in non-muscle tissues and cells. Cell Biol 193-220.
Walpurgis K, Thomas A, Laussmann T et al. (2011) Identification of fibroblast growth factor 1 (FGF‐1) in a black market product. Drug Test Anal 3(11-12), 791-797.
Wells DJ (2008) Gene doping: the hype and the reality. Br J Pharmacol 154(3), 623-631.
Wiggans GR, Misztal I, Van Tassell CP (2003) Calving ease (Co)variance components for a sire-maternal grandsire threshold model. J Dairy Sci 86(5), 1845-1848.
Wilkin T, Baoutina A, Hamilton N (2017) Equine performance genes and the future of doping in horseracing. Drug Test Anal 9(9), 1456-1471.
Wilsher S, Allen WR, Wood JLN (2006) Factors associated with failure of Thoroughbred horses to train and race. Equine Vet J 38(2), 113-118.
Wirth T, Parker N, Ylä-Herttuala S (2013) History of gene therapy. Gene 525(2), 162-169.
Wong JKY, Wan TSM (2014) Doping control analyses in horseracing: A clinician’s guide. Vet J 200(1), 8-16.
Yan Z, Okutsu M, Akhtar YN et al. (2011) Regulation of exercise-induced fiber type transformation, mitochondrial biogenesis, and angiogenesis in skeletal muscle. J Appl Physiol 110(1), 264-274.
Yang N, MacArthur DG, Gulbin JP et al. (2003) ACTN3 genotype is associated with human elite athletic performance. Am J Hum Genet 73(3), 627-631.
Yeh JL, Giordano FJ (2003) Gene-based therapeutic angiogenesis. Thorac Cardiovasc Surg 15(3), 236-249.