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Maniego J, Harding C, Habershon-Butcher J, Hincks P, Ryder E. Administration and detection of a multi-target rAAV gene doping vector in horses using multiple matrices and molecular techniques. Gene Ther 2024:10.1038/s41434-024-00462-0. [PMID: 38972888 DOI: 10.1038/s41434-024-00462-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 06/18/2024] [Accepted: 06/25/2024] [Indexed: 07/09/2024]
Abstract
Gene doping, which includes the non-therapeutic use of genes or genetic elements that have the capacity to enhance athletic performance, is prohibited in horseracing and equestrian sports. To provide a comprehensive assessment of matrix and detection techniques, a custom adeno-associated virus serotype 8 vector was designed to include PCR binding sites for multiple target genes and assay types. The vector was injected via an intramuscular route into two Thoroughbred horses and matrices collected at defined timepoints. DNA was analysed using 3 detection methods: qPCR, digital PCR, and NGS. Overall, there was a strong correlation across the different detection methods employed, although digital PCR was less sensitive at lower concentrations. High concentrations of vector were detected at early timepoints in plasma and whole blood, which rapidly dropped after 0.5 d to trace levels by 4 d and 9 d post-administration respectively, following a similar pattern to previous studies. Vector was detected in dried blood spots at lower levels than whole blood, but with a similar detection time. Detection in hair root bulbs in one horse was observed at over a month post-administration, which opens new avenues for future gene doping testing in humans and animals.
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Affiliation(s)
- Jillian Maniego
- Sport and Specialised Analytical Services, LGC, Newmarket Road, Fordham, Cambridgeshire, CB7 5WW, UK
| | - Caitlin Harding
- Sport and Specialised Analytical Services, LGC, Newmarket Road, Fordham, Cambridgeshire, CB7 5WW, UK
| | | | - Pamela Hincks
- Sport and Specialised Analytical Services, LGC, Newmarket Road, Fordham, Cambridgeshire, CB7 5WW, UK
| | - Edward Ryder
- Sport and Specialised Analytical Services, LGC, Newmarket Road, Fordham, Cambridgeshire, CB7 5WW, UK.
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2
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Yuen BPN, Wong KS, So YM, Kwok WH, Cheung HW, Wan TSM, Ho ENM, Wong WT. Gene Doping Control Analysis of Human Erythropoietin Transgene in Equine Plasma by PCR-Liquid Chromatography High-Resolution Tandem Mass Spectrometry. Anal Chem 2024; 96:5307-5314. [PMID: 38504497 DOI: 10.1021/acs.analchem.4c00247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
Gene doping involves the misuse of genetic materials to alter an athlete's performance, which is banned at all times in both human and equine sports. Quantitative polymerase chain reaction (qPCR) assays have been used to control the misuse of transgenes in equine sports. Our laboratory recently developed and implemented duplex as well as multiplex qPCR assays for transgenes detection. To further advance gene doping control, we have developed for the first time a sensitive and definitive PCR-liquid chromatography high-resolution tandem mass spectrometry (PCR-LC-HRMS/MS) method for transgene detection with an estimated limit of detection of below 100 copies/mL for the human erythropoietin (hEPO) transgene in equine plasma. The method involved magnetic-glass-particle-based extraction of DNA from equine plasma prior to PCR amplification with 2'-deoxyuridine 5'-triphosphate (dUTP) followed by treatments with uracil DNA glycosylase and hot piperidine for selective cleavage to give small oligonucleotide fragments. The resulting DNA fragments were then analyzed by LC-HRMS/MS. The applicability of this method has been demonstrated by the successful detection of hEPO transgene in a blood sample collected from a gelding (castrated male horse) that had been administered the transgene. This novel approach not only serves as a complementary method for transgene detection but also paves the way for developing a generic PCR-LC-HRMS/MS method for the detection of multiple transgenes.
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Affiliation(s)
- Bruce Pui-Nam Yuen
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin N.T., Hong Kong, China
| | - Kin-Sing Wong
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin N.T., Hong Kong, China
| | - Yat-Ming So
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin N.T., Hong Kong, China
| | - Wai Him Kwok
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin N.T., Hong Kong, China
| | - Hiu Wing Cheung
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin N.T., Hong Kong, China
| | - Terence See Ming Wan
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin N.T., Hong Kong, China
| | - Emmie Ngai-Man Ho
- Racing Laboratory, The Hong Kong Jockey Club, Sha Tin Racecourse, Sha Tin N.T., Hong Kong, China
| | - Wing-Tak Wong
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
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Wilkin T, Hamilton NA, Cawley AT, Bhat S, Baoutina A. PCR-Based Equine Gene Doping Test for the Australian Horseracing Industry. Int J Mol Sci 2024; 25:2570. [PMID: 38473816 DOI: 10.3390/ijms25052570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 03/14/2024] Open
Abstract
The term 'gene doping' is used to describe the use of any unauthorized gene therapy techniques. We developed a test for five likely candidate genes for equine gene doping: EPO, FST, GH1, IGF1, and ILRN1. The test is based on real-time polymerase chain reaction (PCR) and includes separate screening and confirmation assays that detect different unique targets in each transgene. For doping material, we used nonviral (plasmid) and viral (recombinant adeno-associated virus) vectors carrying complementary DNA for the targeted genes; the vectors were accurately quantified by digital PCR. To reduce non-specific amplification from genomic DNA observed in some assays, a restriction digest step was introduced in the PCR protocol prior to cycling to cut the amplifiable targets within the endogenous genes. We made the screening stage of the test simpler and faster by multiplexing PCR assays for four transgenes (EPO, FST, IGF1, and ILRN1), while the GH1 assay is performed in simplex. Both stages of the test reliably detect at least 20 copies of each transgene in a background of genomic DNA equivalent to what is extracted from two milliliters of equine blood. The test protocol was documented and tested with equine blood samples provided by an official doping control authority. The developed tests will form the basis for screening official horseracing samples in Australia.
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Affiliation(s)
- Tessa Wilkin
- National Measurement Institute, Lindfield, NSW 2070, Australia
- Faculty of Veterinary Science, University of Sydney, Camperdown, NSW 2006, Australia
| | - Natasha A Hamilton
- Faculty of Veterinary Science, University of Sydney, Camperdown, NSW 2006, Australia
- Equine Genetics Research Centre, Racing Australia, Sydney, NSW 2000, Australia
| | - Adam T Cawley
- Australian Racing Forensic Laboratory, Racing NSW, Sydney, NSW 2000, Australia
- Racing Analytical Services Limited, Flemington, VIC 3031, Australia
| | - Somanath Bhat
- National Measurement Institute, Lindfield, NSW 2070, Australia
| | - Anna Baoutina
- National Measurement Institute, Lindfield, NSW 2070, Australia
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4
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Lu Y, Yan J, Ou G, Fu L. A Review of Recent Progress in Drug Doping and Gene Doping Control Analysis. Molecules 2023; 28:5483. [PMID: 37513354 PMCID: PMC10386588 DOI: 10.3390/molecules28145483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/11/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
The illicit utilization of performance-enhancing substances, commonly referred to as doping, not only infringes upon the principles of fair competition within athletic pursuits but also poses significant health hazards to athletes. Doping control analysis has emerged as a conventional approach to ensuring equity and integrity in sports. Over the past few decades, extensive advancements have been made in doping control analysis methods, catering to the escalating need for qualitative and quantitative analysis of numerous banned substances exhibiting diverse chemical and biological characteristics. Progress in science, technology, and instrumentation has facilitated the proliferation of varied techniques for detecting doping. In this comprehensive review, we present a succinct overview of recent research developments within the last ten years pertaining to these doping detection methodologies. We undertake a comparative analysis, evaluating the merits and limitations of each technique, and offer insights into the prospective future advancements in doping detection methods. It is noteworthy that the continual design and synthesis of novel synthetic doping agents have compelled researchers to constantly refine and innovate doping detection methods in order to address the ever-expanding range of covertly employed doping agents. Overall, we remain in a passive position for doping detection and are always on the road to doping control.
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Affiliation(s)
- Yuze Lu
- Laboratory of Biochemistry, School of Physical Education, China University of Geosciences, Wuhan 430074, China
| | - Jiayu Yan
- Laboratory of Biochemistry, School of Physical Education, China University of Geosciences, Wuhan 430074, China
| | - Gaozhi Ou
- Laboratory of Biochemistry, School of Physical Education, China University of Geosciences, Wuhan 430074, China
| | - Li Fu
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
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Ohnuma A, Tozaki T, Kikuchi M, Ishige T, Kakoi H, Hirota KI, Takahashi Y, Nagata SI. Multiplex Detection of Transgenes Using πCode Technology for Gene Doping Control. Anal Chem 2023. [PMID: 37379520 DOI: 10.1021/acs.analchem.3c00988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
To ensure fair competition and sports integrity, gene doping is prohibited in horseracing and equine sports. One gene doping method is by administering exogenous genes, called transgenes, to postnatal animals. Although several transgene detection methods have been developed for horses, many are unsuitable for multiplex detection. In this proof-of-concept study, we developed a highly sensitive and multiplex transgene detection method using multiple πCode with identification patterns printed on the surface. The following steps were employed: (1) multiplex polymerase chain reaction amplification of 12 targeted transgenes in a single tube, (2) detection using a mixture of 12 probes labeled with different πCodes, and (3) median fluorescence intensity measurement of fluorescent πCodes. Twelve transgenes cloned into plasmid vectors were targeted, and 1500 copies of each plasmid were spiked into 1.5 mL of horse plasma. Subsequently, a novel method using πCode succeeded in detecting all the transgenes using their DNA extracts. Additionally, we detected the erythropoietin (EPO) transgene in blood samples from a horse administered solely with the EPO transgene using this method. Therefore, the πCode detection method is considered suitable for multitarget gene detection in gene doping tests.
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Affiliation(s)
- Aoi Ohnuma
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsurutamachi, Utsunomiya, Tochigi 320-0851, Japan
| | - Teruaki Tozaki
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsurutamachi, Utsunomiya, Tochigi 320-0851, Japan
| | - Mio Kikuchi
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsurutamachi, Utsunomiya, Tochigi 320-0851, Japan
| | - Taichiro Ishige
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsurutamachi, Utsunomiya, Tochigi 320-0851, Japan
| | - Hironaga Kakoi
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsurutamachi, Utsunomiya, Tochigi 320-0851, Japan
| | - Kei-Ichi Hirota
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsurutamachi, Utsunomiya, Tochigi 320-0851, Japan
| | - Yuji Takahashi
- Equine Research Institute, Japan Racing Association, 1400-4 Shiba, Shimotsuke, Tochigi 329-0412, Japan
| | - Shun-Ichi Nagata
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2 Tsurutamachi, Utsunomiya, Tochigi 320-0851, Japan
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Processes in Doping System: Quantification Reports in Mixed Martial Arts Fighters. Processes (Basel) 2022. [DOI: 10.3390/pr10122734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Mixed martial arts (MMA) has always been surrounded by controversy due to the unusual muscle development of its participants, so it is crucial to know the strategies that have been implemented to reduce doping cases. The main purpose of this paper is to describe the various cases of doping detected by USADA in UFC MMA participants. In addition, strategies that are being developed to reduce cases of positive doping are proposed. From the UFC USADA database, doping cases were extracted, obtaining the substance or substances involved; the formula, physiological effect and the athletes involved; the dates of the sampling; if it was out of competition or in-competition and the sanction time. The substances that were most involved were found to be Ostarine (22), Clomiphene (9), Diuretics (10) and Stanozolol (9). Some sanctions were diminished because they were treated with contamination of supplements (cases of Ostarine) and cases of contamination of meat (Clomiphene). When contaminated supplements were reported, they were added to the list of high-risk supplements maintained as part of USADA’s online dietary supplement safety education and awareness resource—Supplement 411. There were also cases in which positive doping could be avoided through the early report of therapeutic use exemptions. The methodology that the USADA has implemented allows us to register the athletes with positive doping, check the risk of the supplements before being bought and provide a teaching portal. These efforts are necessary to implement in all countries in which MMA is practiced, avoiding the participation of doped martial artists.
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Yan J, Xu Z, Zhou H, Li T, Du X, Hu R, Zhu J, Ou G, Li Y, Yang Y. Integration of CRISPR/Cas12a and Multiplexed RPA for Fast Detection of Gene Doping. Anal Chem 2022; 94:16481-16490. [DOI: 10.1021/acs.analchem.2c04079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Jiayu Yan
- Lab of Biochemistry, School of Physical Education, China University of Geosciences, Wuhan 430074, China
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology - Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Zhichen Xu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology - Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Hu Zhou
- Department of Gynecological Oncology, National Clinical Research Center for Obstetrics and Gynecology, Cancer Biology Research Center (Key Laboratory of the Ministry of Education), Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430070, China
| | - Tao Li
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology - Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Xincheng Du
- Lab of Biochemistry, School of Physical Education, China University of Geosciences, Wuhan 430074, China
| | - Rui Hu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology - Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Jiang Zhu
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology - Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Gaozhi Ou
- Lab of Biochemistry, School of Physical Education, China University of Geosciences, Wuhan 430074, China
| | - Ying Li
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology - Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 10049, China
| | - Yunhuang Yang
- State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, National Centre for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology - Wuhan National Laboratory for Optoelectronics, Chinese Academy of Sciences, Wuhan 430071, China
- University of Chinese Academy of Sciences, Beijing 10049, China
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Tozaki T, Ohnuma A, Nakamura K, Hano K, Takasu M, Takahashi Y, Tamura N, Sato F, Shimizu K, Kikuchi M, Ishige T, Kakoi H, Hirota KI, Hamilton NA, Nagata SI. Detection of Indiscriminate Genetic Manipulation in Thoroughbred Racehorses by Targeted Resequencing for Gene-Doping Control. Genes (Basel) 2022; 13:genes13091589. [PMID: 36140757 PMCID: PMC9498419 DOI: 10.3390/genes13091589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
The creation of genetically modified horses is prohibited in horse racing as it falls under the banner of gene doping. In this study, we developed a test to detect gene editing based on amplicon sequencing using next-generation sequencing (NGS). We designed 1012 amplicons to target 52 genes (481 exons) and 147 single-nucleotide variants (SNVs). NGS analyses showed that 97.7% of the targeted exons were sequenced to sufficient coverage (depth > 50) for calling variants. The targets of artificial editing were defined as homozygous alternative (HomoALT) and compound heterozygous alternative (ALT1/ALT2) insertion/deletion (INDEL) mutations in this study. Four models of gene editing (three homoALT with 1-bp insertions, one REF/ALT with 77-bp deletion) were constructed by editing the myostatin gene in horse fibroblasts using CRISPR/Cas9. The edited cells and 101 samples from thoroughbred horses were screened using the developed test, which was capable of identifying the three homoALT cells containing 1-bp insertions. Furthermore, 147 SNVs were investigated for their utility in confirming biological parentage. Of these, 120 SNVs were amenable to consistent and accurate genotyping. Surrogate (nonbiological) dams were excluded by 9.8 SNVs on average, indicating that the 120 SNV could be used to detect foals that have been produced by somatic cloning or embryo transfer, two practices that are prohibited in thoroughbred racing and breeding. These results indicate that gene-editing tests that include variant calling and SNV genotyping are useful to identify genetically modified racehorses.
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Affiliation(s)
- Teruaki Tozaki
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2, Tsurutamachi, Utsunomiya 320-0851, Japan
- Correspondence:
| | - Aoi Ohnuma
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2, Tsurutamachi, Utsunomiya 320-0851, Japan
| | - Kotono Nakamura
- Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1-1, Yanagido, Gifu 501-1193, Japan
| | - Kazuki Hano
- Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1-1, Yanagido, Gifu 501-1193, Japan
| | - Masaki Takasu
- Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, 1-1, Yanagido, Gifu 501-1193, Japan
| | - Yuji Takahashi
- Equine Research Institute, Japan Racing Association, 1400-4, Shiba, Shimotsuke 329-0412, Japan
| | - Norihisa Tamura
- Equine Research Institute, Japan Racing Association, 1400-4, Shiba, Shimotsuke 329-0412, Japan
| | - Fumio Sato
- Equine Research Institute, Japan Racing Association, 1400-4, Shiba, Shimotsuke 329-0412, Japan
| | - Kyo Shimizu
- Registration Department, Japan Association for International Racing and Stud Book, 4-5-4, Shimbashi, Minato, Tokyo 105-0004, Japan
| | - Mio Kikuchi
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2, Tsurutamachi, Utsunomiya 320-0851, Japan
| | - Taichiro Ishige
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2, Tsurutamachi, Utsunomiya 320-0851, Japan
| | - Hironaga Kakoi
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2, Tsurutamachi, Utsunomiya 320-0851, Japan
| | - Kei-ichi Hirota
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2, Tsurutamachi, Utsunomiya 320-0851, Japan
| | - Natasha A. Hamilton
- Equine Genetics Research Centre, Racing Australia, 2 Randwick Way, Scone, NSW 2337, Australia
| | - Shun-ichi Nagata
- Genetic Analysis Department, Laboratory of Racing Chemistry, 1731-2, Tsurutamachi, Utsunomiya 320-0851, Japan
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Tozaki T, Ohnuma A, Kikuchi M, Ishige T, Kakoi H, Hirota KI, Kusano K, Nagata SI. Identification of processed pseudogenes in the genome of Thoroughbred horses: Possibility of gene-doping detection considering the presence of pseudogenes. Anim Genet 2022; 53:183-192. [PMID: 35077588 DOI: 10.1111/age.13174] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/24/2021] [Accepted: 01/10/2022] [Indexed: 12/15/2022]
Abstract
Processed pseudogenes, also known as retrocopy genes, are copies of messenger RNAs that have been reverse transcribed into DNA and inserted into the genome. In this study, we identified 62 processed pseudogene candidates as intron-less genes from whole-genome sequencing (WGS) data of Thoroughbred horses using delly structural variation software. The 62 processed pseudogene candidates were confirmed by PCR amplification of intron-less products. A total of 11 processed pseudogenes were confirmed in the genome of all 23 analysed horses, whereas three processed pseudogenes with structures of ATP11B, DPH3 and RPL17 were detected in only one of 115 horses by PCR amplification of intron-less products. Currently, most of the gene doping tests proposed in human and horse sports are adapted PCR-based methods using hydrolysis probes to detect exon/exon junctions in transgenes because the operation is simple and economical. However, when the pseudogene is present in the host genome, the PCR-based methods may have a potential risk of detecting false positives. In this study, because processed pseudogenes that exist less frequently in the horse genome may affect PCR-based transgene detection in gene-doping tests, we propose and demonstrate that PCR amplification and sequencing using primers designed on transgene and promotors and/or polyadenylation signal for gene expression are useful for gene-doping detection as an additional confirmatory test to prevent false positives.
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Affiliation(s)
- Teruaki Tozaki
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
| | - Aoi Ohnuma
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
| | - Mio Kikuchi
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
| | - Taichiro Ishige
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
| | - Hironaga Kakoi
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
| | - Kei-Ichi Hirota
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
| | - Kanichi Kusano
- Equine Department, Japan Racing Association, Minato, Tokyo, Japan
| | - Shun-Ichi Nagata
- Genetic Analysis Department, Laboratory of Racing Chemistry, Utsunomiya, Tochigi, Japan
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