Date of Publication


Degree Type

Honors Thesis



First Advisor

Dr. Rey Sia, Department Chair, Biology


The homologs that humans share with Saccharomyces cerevisiae render yeast an ideal model organism to investigate the potential importance of genes in humans. SGS1 is a nuclear gene for a RecQ helicase in yeast, known to play a role in homologous recombination in nuclear genome repair. The research in question is intended to evaluate if SGS1 has a similar importance in mitochondrial genome repair. These conclusions can be employed to better understand the disease phenotypes that humans present as a result from mitochondrial malfunction. A respiration loss assay showed that SGS1 knockout strains have a ~2.2 fold increase in spontaneous respiration loss frequency, indicating that SGS1 plays a role in mitochondrial genome stability. A direct-repeat mediated deletion assay proves SGS1 is involved in homologous recombination in mitochondria due to an ~1.6 fold decrease in rate of homologous recombination in SGS1 knockout strains. With a p value of 0.66, no significant difference was observed in an induced direct-repeat mediated deletion assay between wild type and sgs1Δ strains, implying that SGS1 does not play a fundamental role in double strand break repair. Future experimentation could include additional knockout strains testing other genes known to be involved in nuclear homologous recombination repair and double knockout strains to assess the relative order of active proteins involved in genetic repair mechanisms.


This thesis will be embargoed for 1 year to allow for publication of data included within.