Presumed monozygotic twins develop following transfer of an in vitro-produced equine embryo.
Abstract: An equine embryo produced by intracytoplasmic sperm injection (ICSI) was trans-cervically transferred to a recipient mare and pregnancy was confirmed via ultrasound examination on days 11, 12 and 15. On days 20 and 22, a single embryonic proper with a heartbeat was observed. On day 29, two embryos proper appeared during ultrasound examination, each possessing a heartbeat. Subsequent examinations on days 35 and 39 revealed continued viability and development of both embryos proper. On day 49, demise of both fetuses was present. Although no DNA analysis or post-partum examinations were performed, it is presumed that the fetuses were monozygotic twins based on membrane classification by ultrasound imaging as well as development occurring after the transfer of a single in vitro-produced embryo.
Publication Date: 2015-09-30 PubMed ID: 26435682PubMed Central: PMC4591415DOI: 10.1294/jes.26.89Google Scholar: Lookup
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- Journal Article
Summary
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The research examines a case where one horse embryo, developed through assisted reproduction methods, was transferred to a mare and resulted in what is presumed as identical twin embryos, which unfortunately did not survive past early development.
Methods Involved and Observations Made
- The researchers created a horse embryo through a method known as intracytoplasmic sperm injection (ICSI), which involves injecting a single sperm into a mature egg under a microscope.
- This embryo was then transferred into a mare’s cervix using a minimally invasive procedure known as a trans-cervical transfer, typically performed in a clinical setting.
- After the transfer, the mare’s pregnancy was confirmed through ultrasound examinations on days 11, 12, and 15.
- Different stages of embryonic development were observed and recorded on days 20, 22, 29, 35, and 39. On day 20 and 22, a single embryo was seen with a functioning heartbeat. On day 29, this embryo had become two separate embryos, each with its own heartbeat.
- Unfortunately, by day 49, both fetuses were no longer viable.
Presumed Monozygotic Twins
- The major finding from this study was the appearance of two separate embryos from a single in vitro-produced embryo. According to ultrasound images and membrane classification, the researchers assumed these to be monozygotic, or identical, twins.
- Usually, monozygotic twins occur when a single fertilized egg splits into two separate embryos at an early stage in development, which then continue to develop into two identical fetuses.
- This type of twinning, when it occurs in horses, can present challenges as equine pregnancies are physically structured and designed to support the growth and development of a single fetus.
- As such, monozygotic twins are very rare in horses and when they do occur, often lead to complications that can compromise the health and viability of the foals and the mare.
Limitations
- Despite these visually compelling observations, the study did not perform postmortem examinations or DNA analysis to conclusively prove that the fetuses were monozygotic twins.
- The researchers’ assertion is based on their interpretation of ultrasound images and the unlikely occurrence of this form of twinning following the transfer of a lone embryo.
Cite This Article
APA
Roberts MA, London K, Campos-Chillón LF, Altermatt JL.
(2015).
Presumed monozygotic twins develop following transfer of an in vitro-produced equine embryo.
J Equine Sci, 26(3), 89-94.
https://doi.org/10.1294/jes.26.89 Publication
Researcher Affiliations
- Department of Animal Science, California Polytechnic State University, CA 93407, U.S.A.
- Department of Animal Science, California Polytechnic State University, CA 93407, U.S.A.
- Department of Animal Science, California Polytechnic State University, CA 93407, U.S.A.
- Department of Dairy Science, California Polytechnic State University, CA 93407, U.S.A.
References
This article includes 15 references
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Citations
This article has been cited 2 times.- Meinecke B, Meinecke-Tillmann S. Lab partners: oocytes, embryos and company. A personal view on aspects of oocyte maturation and the development of monozygotic twins. Anim Reprod 2023;20(2):e20230049.
- Dijkstra A, Cuervo-Arango J, Stout TAE, Claes A. Monozygotic multiple pregnancies after transfer of single in vitro produced equine embryos. Equine Vet J 2020 Mar;52(2):258-261.
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