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Date Permissions Signed

2-17-2016

Date of Award

Winter 2016

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Kodner, Robin

Second Advisor

Moyer, Craig L.

Third Advisor

Fizzano, Perry

Abstract

Insufficient reference sequence data for annotation of unknown environmental sequences and metagenomes has driven efforts to find alternative annotation methods that mitigate biases from missing information. The use of phylogenetic-placement algorithms shows promise as a robust sequence annotation technique that deals with missing reference information by allowing for annotation of sequences at internal nodes of a phylogenetic tree. However, using these methods for community level surveys of the thousands of genes found in metagenomes requires powerful computational systems and sophisticated software workflows. The main goal of this thesis is to outline a phylogenetic analysis pipeline built to process environmental metagenomic samples using the pplacer software suite, and a pilot study performed with this software pipeline to investigate community-level patterns in gene diversity for a marine oxygen minimum zone (OMZ) off the coast of Chile, South America. Reference sequence data was used to create a custom database and custom reference packages for 9,204 functional housekeeping genes, along with small sub-unit ribosomal genes (SSU) by Domain. A comparative analysis of metagenomic samples from the OMZ using our pipeline shows that while functional and SSU genes show similar spatial patterns of diversity across the oxygen gradient, higher overall diversity was identified via the functional genes. Ecologically relevant functional genes showed higher levels of diversity than either the total from all functional genes or SSU ribosomal genes, underlining the importance of diversity in ecosystem functions.

Type

Text

Publisher

Western Washington University

OCLC Number

940994262

Digital Format

application/pdf

Geographic Coverage

Chile

Genre/Form

Academic theses

Language

English

Language Code

eng

Rights

Copying of this thesis in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

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Biology Commons

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