Interested Members of the University Community are invited to attend the Final Oral Examination for the Degree of Master of Science of Bioinformatics Nia Hughes 

Date: Thursday, September 3rd at 1:00 PM

Thesis title: Variation in Methylation Patterns Between Maize mop1 Mutants

Chair:     Dr. Steffen Graether

Advisor:  Dr. Lewis Lukens

If you are interested in participating in this defense, please e-mail slakhan@uoguelph.ca to be added to the TEAMS calendar invitation

ABSTRACT

In maize, the delicate balance between gene expression and near-gene transposon silencing is maintained largely through regulation by the RNA-directed DNA methylation (RdDM) pathway. Loss of RdDM through knockout of the mediator of paramutation 1 (mop1) gene has been demonstrated to cause widespread, non-lethal changes to the maize epigenome, but little is known about whether and how RdDM activity is affected by genotypic background. Bisulfite sequencing data from three inbred lines in both wild-type and mop1-defective mutant states were analyzed to refine our understanding of mop1 targets and to examine whether methylation patterns differ across genomes suffering loss of RdDM. Genotypes showed an unexpectedly high amount of variability in their relative methylation change across genes and transposable element subfamilies. Additionally, the set of genes under direct mop1-mediated regulation were characterized, and a novel set of RdDM-associated epialleles were discovered. This research suggests that RdDM has previously unreported genotype-specific effects, both globally and at particular loci.