Honors Theses and Capstones
Date of Award
Spring 2014
Project Type
Senior Honors Thesis
College or School
COLSA
Department
Biological Sciences
Program or Major
Biomedical Sciences: Medical Microbiology
Degree Name
Bachelor of Science
First Advisor
Vaughn Cooper
Second Advisor
Marcus Dillon
Abstract
Mutations that improve fitness in one environment can often be beneficial, deleterious, or neutral in alternative environments. When a single mutation effects fitness in multiple environments, it is said to be a pleiotropic, which can have important consequences for niche specialization, niche expansion, speciation, and even extinction in the face of environmental change. While previous studies have revealed that pleiotropy is nearly universal, the role of adaptive history in the spectrum of pleiotropic effects has yet to undergo detailed experimental observation. Using experimental evolution we gathered beneficial mutations in a previously adapted strain of Escherichia coli growing in the same common substrate over hundreds of generations. We then tested the effects of these mutations in multiple alternative environments and compared their fitness to the ancestor. We found that the magnitude of the effects correlates positively with the similarity of resources to glucose, indicating that selective history has an influence in the distribution of beneficial mutations. These findings broaden our understanding of the effects of history on pleiotropy, and may provide answers into how evolution in a constant environment influences ecological niche formation and constraint.
Recommended Citation
Van Dam, Brian Scott, "The Pleiotropic Effects of Beneficial Mutations of Adapted Escherichia coli Populations" (2014). Honors Theses and Capstones. 191.
https://scholars.unh.edu/honors/191