Bayer School of Natural and Environmental Sciences
Epigenetics, Maize, Methylation, Paramutation, R-standard, R-stippled
Paramutation occurs between trans-alleles with homologous sequences resulting in a heritable change in gene expression, where epigenetic information from one allele is passed to the other. In maize, the paramutagenic r1 allele, R-stippled, silences the paramutable allele, R-r:standard, following paramutation. The R-r:standard allele is known to show increased methylation following paramutation. The R-stippled allele, which is composed of the four genes, Sc, Nc1, Nc2 and Nc3, becomes less paramutagenic as genes are lost. Sc alone is not paramutagenic. I hypothesized that the R-stippled derivative containing two genes would be less methylated at cytosine residues than the four-copy allele, particularly in the 5' region. Analysis of the methylation patterns between the two gene lines and the four gene line showed no distinct differences in methylation, suggesting that it is not methylation differences responsible for paramutagenicity differences. Paramutagenicity testes confirmed that as r gene number decreases, the paramutagenic strength decreases.
Dragone, K. (2013). Methylation Patterns and Phenotypes of the R-stippled Derivatives Lines (Master's thesis, Duquesne University). Retrieved from https://dsc.duq.edu/etd/502