Undergraduate Honors Theses

Thesis Defended

Spring 2016

Document Type


Type of Thesis

Departmental Honors


Molecular, Cellular, & Developmental Biology

First Advisor

Shelley Copley


Catalytic promiscuity provides a starting point for the evolution of new enzymes. When a secondary “promiscuous” activity becomes physiologically relevant, selection will favor genetic changes that improve upon this promiscuous activity. When the ability to do both activities limits growth, it is an inefficient bi-functional enzyme. The Copley lab at the University of Colorado at Boulder has found several genetic changes that increase fitness in a ΔargC strain of Escherichia coli BW25113 when growth is limited by an inefficient bi-functional enzyme (ProA*). The experiments described in this thesis investigate the genetic changes that increase fitness in a ΔargC strain of Salmonella enterica subsp. enterica serovar Typhimurium str. SL1344 when limited by a similar inefficient bi-functional enzyme. In addition to identifying specific genetic changes, I aim to investigate how differences in the genetic background and physiology of the organism affect what changes are selected for and the adaptive potential of such changes.