Date of Award

January 2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Jefferson A. Vaughan

Abstract

The family Onchocercidae is a group of parasitic vector born nematodes that are split up into eight subfamilies. Although the subfamilies containing species that parasitize humans and livestock (e.g., Onchocercinae) have been well-studied, there is a considerable lack of information for the lesser studied subfamilies in Onchocercidae (e.g. Waltonellinae). This uncertainty leaves some doubt as to the phylogenetic and evolutionary relationships among the different taxonomic groupings of filarioid nematodes.

I worked with two species of the subfamily Waltonellinae, Foleyellides n. sp. and F. flexicauda. The primers used in this study for polymerase chain reactions (PCR) and DNA sequencing reactions were based on previously published sources and newly designed as needed. DNA products having the predicted molecular size were used for sequencing reactions. Sequencing was performed using appropriate primers in order to cover the entire mitochondrial genome. Obtained sequences were assembled into a complete circular mitochondrial genome with exception of a small AT-rich region. Phylogenetic analyses using Baysian inference and other algorithms was performed to determine phylogenetic affinities of newly sequenced nematodes with the previously sequenced filarioids. Both genome-level and gene-level phylogenies were produced and compared.

Foleyellides n. sp. and F. flexicauda were often found to be the basal branch of the phylogenies. This, along with the fact that neither species is Wolbachia-dependent, suggests Waltonellinae was one of the first filarioid nematode groups to exist within the nematode family.

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