Defense Date

5-24-2013

Graduation Date

Summer 2013

Availability

Immediate Access

Submission Type

thesis

Degree Name

MS

Department

Biological Sciences

Committee Chair

Michael Seaman

Committee Member

David Lampe

Committee Member

William Eggleston

Keywords

Epigenetics, Maize, Methylation, Paramutation, R-standard, R-stippled

Abstract

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.

Format

PDF

Language

English

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