Publication Date

2017-5

Document Type

Honors Thesis

Degree Name

Bachelor of Arts

Department

Biological Sciences

Advisors

Laura A. Katz

Keywords

Genome architecture, Extensive chromosomal fragmentation, High-throughput sequencing, Microbes, Ciliates, Bioinformatics, Genetics, Genomes, Fragmentation reaction, Microorganisms

Abstract

Protists are immensely diverse and largely understudied unicellular eukaryotic microorganisms. They inhabit nearly every ecological niche on Earth and play central roles within their ecosystems as bioindicators, primary producers, predators, and even potential reservoirs for symbiotic bacteria and viruses. Although the dominant literature prioritizes plants, animals and fungi, protists constitute the bulk of diverse eukaryotic lineages - yet remain largely understudied. Ciliates, the focus of this study, are a diverse clade of microbial eukaryotes with dimorphic nuclei and unusual genomic processing, making them of key interest to genomic studies. These interesting genome features challenge assumptions about eukaryotic diversity and offer additional insight into conventional eukaryotic models.

This study uses a combination of molecular tools and bioinformatics to characterize the genome structure of ciliates in the class Litostomatea. The first component uses a PCR-based approach to assess chromosome size in the somatic genome. The second component uses single cell ‘omics to analyze the structure of the chromosomes and their hypothetical function. The results of this thesis support the notion of extensive fragmentation in the somatic genome of litostome ciliates; extensively fragmented ‘gene-sized’ chromosomes contain a motif that may regulate telomere synthesis and chromosome breakage rather than transcription of expressed genes. Extensive processing of the somatic genome has not been previously reported in the class Litostomatea and may provide new information to the evolution of this trait in various ciliate lineages. More broadly, further studies into the mechanisms underlying large-scale genome rearrangements in litostome ciliates may link this mechanism to its counterparts in other eukaryotes.


Language

English

Comments

43 pages : color illustrations. Includes bibliographical references (pages 40-43)

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