Date of Award

Spring 2004

Document Type

Restricted Thesis

Terms of Use

© 2004 Jessica A. Tashjian. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Biology Department

First Advisor

Elizabeth Ann Vallen


The protein Sid2/Cdt1 plays an essential role in licensing DNA replication in Saccharomyces cerevisiae. We have attempted to identify four dominant suppressors of a mutation in sid2. To map the location of the suppressors, we constructed suppressor-containing 'query strains' that were crossed to an arrayed set of approximately 700 marked deletion strains. The resulting progeny were analyzed for recombination. The absence of recombinants between the suppressor and the marked deletion suggested that the two were linked. The frequency of recombination of possible linkages was quantified with random spore analysis, and confirmed by tetrad dissection. A region likely to contain two suppressors was identified and divided into eight sub-regions. Transformation of PCR fragments containing the relevant DNA fragments is being used to determine which sub-region can confer suppression to a sid2-2lᵗˢ strain. Six of the sub-regions have been ruled out, and the remaining two are undergoing further analysis to identify the gene encoding the suppressor.