Exploring methods to understand bovine embryo competency in vitro

Simple item page
dc.contributor.authorNix, Jada Lindsayen
dc.contributor.committeechairBiase, Fernando H.en
dc.contributor.committeememberRhoads, Michelleen
dc.contributor.committeememberEaly, Alan Daleen
dc.contributor.departmentAnimal and Poultry Sciencesen
dc.date.accessioned2023-12-20T09:00:21Zen
dc.date.available2023-12-20T09:00:21Zen
dc.date.issued2023-12-19en
dc.description.abstractThe development of a preimplantation embryo is a stepwise process consisting of morphological, biochemical, and genomic changes. Much remains unknown about the attainment of embryo competency to develop and establish pregnancy. To investigate this, we compared methods of selection at the oocyte or embryo level for improved blastocyst production. Brilliant cresyl blue staining was used to sort oocytes by their growth status (not fully grown vs. fully grown) and the timing of the first embryonic cell division to sort embryos. We found that an embryo's cleavage kinetics are more indicative of their competency than the growth status of the oocyte that gave rise to that embryo. We further investigated the cryopreservation survival of embryos with fast or slow cleavage kinetics and found no significant differences in their ability to hatch post-thawing. Next, we used the complete sequence of the cattle Y chromosome to identify oligonucleotides for efficient sexing of samples. These materials may be used to understand sexual dimorphism as a biological factor in future experiments. Finally, we designed a new method to induce targeted DNA sequence deletions and mRNA cleavage in zygotes using CRISPR-Cas. We targeted the gene OCT4, since the literature shows variable knockout outcomes. Our method improved deletion efficiency while accounting for preexisting or maternally inherited mRNA of the target gene. Our findings can be used to better understand early embryo development and biological drivers of quality, which can be leveraged to improve embryo production and transfer outcomes.en
dc.description.abstractgeneralThe development of an early embryo involves many biological and structural changes. Much remains unknown about the influences on embryo quality and ability to successfully develop. To investigate this, we compared methods for selecting the highest quality cattle eggs or embryos. We found that the observation of an embryo's development speed is better for selecting high quality embryos than egg quality. We further investigated the freezing survival of embryos with fast or slow growth. We found that the freezing survival of fast and slow growing embryos is not different. Next, we used the complete sequence of the cattle Y chromosome to identify PCR primers for determining sample sex. These resources can help us understand how an individual's sex can influence biological differences. Finally, we designed a new method for removing the total function of a gene in embryos. For this, we deleted segments of DNA and cut RNAs. Our findings can be used to better understand early embryo development and biological drivers of quality, which can be leveraged to improve embryo production and transfer outcomes.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:39197en
dc.identifier.urihttps://hdl.handle.net/10919/117229en
dc.language.isoenen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectOocyteen
dc.subjectblastocysten
dc.subjectdevelopmental competenceen
dc.subjectgene editingen
dc.subjectCRISPR-Casen
dc.titleExploring methods to understand bovine embryo competency in vitroen
dc.typeThesisen
thesis.degree.disciplineAnimal and Poultry Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Nix_JL_T_2023.pdf
Size:
1.48 MB
Format:
Adobe Portable Document Format
Download

Collections

Masters Theses