Phenotypic and genetic instability of a gene duplication in Arabidopsis thaliana

Project Summary

A duplication of the pathogen Resistance gene SNC1 in Arabidopsis thaliana results in a semi-dominant, curly leaved, dwarfing phenotype called bal.  A 55-kb duplication of the R-gene cluster containing SNC1 was recovered from a ddmt (DNA methylation) mutant background.  The Richards lab has been studying both the formation of the duplication and the unstable bal variant.  Overtime, mutagenized bal plants frequently produce chimeric offspring, called BAL*, that appear part wild-type and part bal.  Previous work from Dr. Richard’s lab using the mutagen ethyl methanesulfonate (EMS) indicates that mutations can inactivate one of the duplicated SNC1 genes, resulting in the chimeric/BAL* phenotype.  The rate of mutation, thus the number of BAL* individuals, is elevated above the expected frequency in mutagenized populations.  My project was to investigate if fast neutron mutagenesis could also induce mutations that inactivate SNC1.  Furthermore, if these mutations occur, where do they occur and are they stably inherited?  To help answer these questions, I employed fast-neutron mutagenesis to generate new BAL* plants.  I sequenced the SNC1 gene in these plants with Polymerase Chain Reaction (PCR) and Sanger sequencing techniques.  This work will likely contribute in the understanding of DNA repair in response to DNA damage.

My Experience

My time with the Richards Lab and the Plant Genome Research Program enabled me  to explore research in plant biology and genetics.  It has been a pleasure to get to know members of the lab and other interns interested in research.  I also enjoyed the chance to learn about many different areas of science through seminars, training, and events.  This internship has encouraged me to pursue graduate studies in plant research after I complete my bachelors degree in biology.