Publication Date

2015

Document Type

Dissertation/Thesis

First Advisor

Duvall, Melvin R.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Biological Sciences

LCSH

Plant sciences; Biology; Genetics; Plants--Phylogeny--Research; Corn--Phylogeny--Research; Chloroplast DNA--Research; Plant mutation--Research

Abstract

This project examines the relationships within the genus Zea using complete chloroplast genomes (plastomes). Zea mays is one of the most widely cultivated crop species in the world. Billions of dollars have been spent in the commercial agriculture sector to study and improve Z. mays.;While Z. mays has been well studied, the congeneric species have yet to be as thoroughly examined. For this study complete plastomes were sequenced in four species (Zea diploperennis, Zea perennis, Zea luxurians, and Zea mays subsp. huehuetenangensis) by Sanger or next-generation methods. An analysis of the microstructural mutations, such as inversions, insertion or deletion mutations (indels) and determination of their frequencies were performed for the complete plastomes.;It was determined that 197 indels and 10 inversions occurred across the examined plastomes. The most common mutational mechanism was discovered to be the tandem repeat from slipped strand mispairing events. Mutation rates were calculated to determine a precise rate over time. The mutations rates for the genus fell within the range of 0.00126 to 0.02830 microstructural mutation events per year. These rates are highly variable, corresponding to the close and complex relationships within the genus.;Phylogenomic analyses were also conducted to examine the differences between species within Zea. In many cases, much of the previous work examining Zea mitochondrial and nuclear data was confirmed with identical tree topologies. Divergence dates for specific nodes relative to Zea were calculated to fall between 8,700 calendar years before present for the subspecies included in this study and 1,024 calendar years before present for the perennial species included in this study.

Comments

Advisors: Melvin R. Duvall.||Committee members: Richard King; Wesley Swingley.

Extent

49 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

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