Genetic Manipulation of the Equine Oocyte and Embryo.
Authors: Hisey Erin A, Ross Pablo J, Meyers Stuart
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Genetic Manipulation of the Equine Oocyte and Embryo The inability to establish routine in vitro fertilisation in horses has prompted researchers to develop alternative embryo creation techniques for both research and potential therapeutic applications. Hisey, Ross and Meyers reviewed five key approaches: parthenogenesis (oocyte maturation without sperm involvement), somatic cell nuclear transfer for cloning, interspecies nuclear transfer, sperm-mediated gene transfer (SMGT) for transgenesis, and CRISPR/Cas9 gene editing—evaluating each method's technical feasibility, limitations and practical utility. Whilst parthenogenesis and SCNT produce genetically identical embryos to donor material, they cannot create targeted genetic modifications; SMGT has successfully generated transgenic equine blastocysts but lacks precision for directed mutations; conversely, CRISPR/Cas9 technology offers the specificity necessary for therapeutic gene modification, though equine applications remain underdeveloped. Interspecies nuclear transfer has proven unsuccessful despite theoretical promise given the chronic shortage of equine oocytes in research settings. For equine professionals involved in breeding, performance optimisation or genetic health programmes, understanding these distinctions matters: cloning and transgenic approaches may eventually address specific breeding goals or disease resistance, whilst emerging gene-editing platforms could fundamentally reshape how we approach heritable conditions—though clinical translation remains several years distant.
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Practical Takeaways
- •Current equine reproductive biotechnology remains primarily research-focused with no established clinical applications for practitioners at this time
- •Gene editing technologies may eventually enable targeted genetic modifications for therapeutic purposes, but clinical translation is not yet available
- •Practitioners should be aware these techniques exist but should not expect near-term practical applications in standard equine breeding or therapy programs
Key Findings
- •Standard in vitro fertilization remains non-viable in horses, necessitating alternative embryo creation techniques for research
- •Parthenogenesis, SCNT, and interspecies SCNT create genetically identical embryos but are limited by oocyte availability and interspecies incompatibility
- •Sperm-mediated gene transfer (SMGT) successfully produces transgenic equine blastocysts but cannot induce targeted mutations
- •CRISPR/Cas9 technology is essential for gene therapy applications requiring targeted mutations in equine embryos