Date of Graduation

5-2015

Document Type

Thesis

Degree Name

Master of Science in Biology (MS)

Degree Level

Graduate

Department

Biological Sciences

Advisor

Frederick W. Spiegel

Committee Member

Steven L. Stephenson

Second Committee Member

Ines Pinto

Keywords

Biological sciences; Amoebozoa; Cockroach; Entamoeba; Microbe; Phylogeny; Protist

Abstract

While the parasitic Amoebozoan Entamoeba histolytica has been well-studied for its role in human pathogenesis, the biodiversity of invertebrate-inhabiting Entamoeba has scarcely been investigated. Using molecular methods, I searched for Entamoeba in the guts of cockroaches from four of the six Blattodean families. Entamoeba small-subunit rRNA genes were recovered from all eight species of cockroaches tested, five of which represent newly discovered hosts. Phylogenetic analysis of over 190 sequences revealed a novel and highly diverse clade of cockroach-inhabiting Entamoeba, separate from the clade predominated by vertebrate-inhabitants. These results double the known genetic diversity of Entamoeba and suggest that they may be widespread among cockroaches. While it would be premature to delineate new species based solely on the sequence data, work on other biologically relevant features of these Entamoeba variants could assist with that.

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