Equine Reproductive Procedures. Группа авторов. Читать онлайн. Newlib. NEWLIB.NET

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Издательство: John Wiley & Sons Limited
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Жанр произведения: Биология
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isbn: 9781119555933
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Chain Reaction Test for the SRY Gene

      In addition to chromosome analysis and karyotyping, it is a common practice in horse cytogenetics laboratories to test each case for the presence or absence of the SRY gene in the Y chromosome. The procedure involves polymerase chain reaction (PCR) with SRY primers and the genomic DNA of the horse in question. The test is useful for cases of sex reversal where a sterile female horse has XY sex chromosomes, with or without the SRY gene. The PCR test can also discover female horses that are mosaic or chimeric for a cell line carrying the Y chromosome.

      Chromosome Analysis Time Line

      Chromosome analysis from blood lymphocytes typically takes 10 working days; analysis from cell lines may take longer depending on the progression of cell cultures. The procedures and the turnaround time for the basic chromosome analysis, however, varies between service laboratories and depends on the complexity of each individual case.

      Advanced Chromosome Analysis

Photo depicts fluorescence in situ hybridization (FISH) (a) with horse X chromosome probes (and red; arrows) in an infertile mare with X-trisomy (65,XXX) and (b) with horse chromosome 30 probes (red; arrows) in a developmentally abnormal colt carrying three copies of chromosome 30 (65,XY+30).

      International Horse Clinical Cytogenetic Laboratories

      Additional Comments and Future Perspectives

      With the availability of the horse genome reference sequence for the past 10 years, several new cutting edge technologies have emerged for horse genome and chromosome analysis. Single nucleotide polymorphism (SNP) arrays can detect aneuploidies and small sub‐chromosomal deletions and duplications at a resolution not achieved by conventional karyotyping or FISH. An even more powerful approach is next generation sequencing (NGS), which allows the analysis of the whole genome sequence of an individual horse. Although SNP arrays and NGS are widely used in horse disease genetics, their application in clinical cytogenetics has been limited, likely because of the relatively high cost and demanding bioinformatics. Also, neither platform is able to ascertain cell to cell variations or accurately resolve mosaic/chimeric cytogenetic patterns.

Country, City Laboratory Director/Principal Investigator Contact
Poland, Krakow Department of Animal Reproduction, Anatomy and Genomics, University of Agriculture Monika Bugno Poniewierska [email protected]
Spain, Cordoba Department of Genetics, University of Cordoba Miguel Moreno‐Millán [email protected]
Canada, Guelph KARYOTEKK, University of Guelph Allan W. King [email protected]; http://www.karyotekk.com/home
USA, Texas, College Station Molecular Cytogenetics, Texas A&M University Terje Raudsepp http://vetmed.tamu.edu/labs/cytogenics‐genomics

      Despite the promises of novel technology, it is unlikely that it will entirely replace conventional and FISH‐based chromosome analysis in horses. Traditional cytogenetics is still the most straightforward and cost‐effective approach and will remain the gold standard for the initial evaluation of breeding animals and individuals with reproductive or developmental disorders.

      1 Arrighi FE, Hsu TC. 1971. Localization of heterochromatin in human chromosomes. Cytogenetics 10: 81–6.

      2 Bowling AT, Breen M, Chowdhary BP, et al. 1997. International system for cytogenetic nomenclature of the domestic horse. Report of the Third International Committee for the Standardization of the domestic horse karyotype, Davis, CA, USA, 1996. Chromosome Res 5: 433–43.

      3 Raudsepp T, Chowdhary BP. 2016. Chromosome aberrations and fertility disorders in domestic animals. Annu Rev Anim Biosci 4: 15–43.

      4 Seabright M. 1971. A rapid banding technique for human chromosomes. Lancet 2: 971–2.

      1 Durkin K, Raudsepp T, Chowdhary B. 2011. Cytogenetic evaluation of the stallion. In: McKinnon AO, Squires EL, Vaala WE, Varner DD (eds). Equine Reproduction, 2nd edn. Ames, IA: Wiley Blackwell, pp. 1462–8.

      2 Lear TL. 2014. Chromosomal analysis. In: Dascanio J, McCue P (eds). Equine Reproductive Procedures, 1st edn. Oxford: John Wiley & Sons, Inc., pp. 77–82.

      3 Lear TL, McGee RB. 2012. Disorders of sexual development in the domestic horse, Equus caballus. Sex Dev 6: 61–71.

      4 Lear