Year of Award

2017

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Cellular, Molecular and Microbial Biology

Other Degree Name/Area of Focus

Microbial Evolution and Ecology

Department or School/College

Division of Biological Sciences

Committee Chair

Scott Miller

Commitee Members

John McCutcheon, Frank Rosenzweig, Jim Elser

Keywords

paralog, copy number variation, dosage, cyanobacteria, RecA, iron

Publisher

University of Montana

Subject Categories

Environmental Microbiology and Microbial Ecology | Evolution | Genomics

Abstract

Acaryochloris is a recently discovered genus of cyanobacteria, unique in its use of an uncommon chlorophyll as its major photosynthetic pigment, and in its peculiar genome dynamics. Members of this genus exhibit increased genic copy number variation (CNV), which is thought to be primarily derived from gene duplications and horizontal gene transfer (HGT). Acaryochloris provides an ideal system to explore mechanisms behind maintenance of gene duplicates and the influence of CNV in local adaptation. Here, I propose a mechanism for retention of gene duplicates of the bacterial recombinase, RecA, in Acaryochloris genomes and provide preliminary evidence that these paralogs are becoming functionally divergent. I then focus on idiosyncratic CNV between two strains of Acaryochloris which were isolated from very different environments. I provide evidence of local adaptation to iron limitation in one strain, associate it with physiological differences between strains, and show that unique CNV drives changes in gene dosage and is associated with variable fitness and physiology.

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© Copyright 2017 Amy L. Gallagher