Investigating Chromosome Organization in Early Stage Zebrafish (Danio Rerio) Embryos

Student: Alyssa Stadie

Faculty Mentor: Lisa Hua

Biology

College of Science, Technology, and Business

In meiosis, homologous chromosomes pair and recombine, exchanging DNA between the same genes to generate distinct sex cells that contribute to genetic diversification. In mitosis, unregulated pairing and recombination between homologous chromosomes can lead to genomic instability (Karpenshif and Bernstein, 2012). It has been discovered that homologous chromosomes and sex chromosomes are spatially separated along centrosomes in dividing human neonatal cells (Hua and Mikawa, 2018). The homologous segregation pattern forms two haploid chromosome sets along either side of the centrosomes. This haploid set organization, or antipairing pattern, may function to prevent abnormal pairing that is associated with abnormal gene misregulation and cancer (Hua and Mikawa, 2018; Koeman, 2018). However, the underlying mechanisms of the antipairing organization remain elusive. A potential mechanism for the haploid set organization is based on parental origin (Hua and Mikawa, 2018). It is currently unknown whether the separation of maternal and paternal genomes persists throughout development. Further investigation is required to test whether parental genomes remain segregated after fertilization and may persist into adulthood. Zebrafish embryos are powerful biomedical research models because they share roughly 70% of their genes with humans (Choi et al., 2021). Their rapid external development and transparent embryos allow for easy collection and observation of fertilization and early embryonic development. We will use genetically modified zebrafish embryos with non-/fluorescently labeled chromosomes to observe maternal and paternal genome interactions during their early embryonic development following fertilization. This research will provide valuable insight into chromosome organization during early development.