Adomako-Ankomah, Yaw
(2014)
COMPARATIVE ANALYSIS OF GENE DUPLICATION: IMPACT OF TANDEMLY DUPLICATED GENES ON TRAIT EVOLUTION IN <TOXOPLASMA GONDII>.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Gene duplication is a well-recognized mechanism by which organisms acquire novel traits and it has been shown to play an important role in species divergence. Recent genomics studies have highlighted the significant impact that gene duplication can have in the adaptive evolution of parasite species. Traits such as drug resistance, host immune evasion and disruption, virulence and host range selection have all been shown to be affected by gene duplication events. However, relatively little is known about the importance of gene duplication in the evolution of protozoan parasites. The goal of this study is to examine the scope and impact of gene duplication on the evolution of unique traits in the human parasite <Toxoplasma gondii>.
To this end, we used comparative genomics approaches to perform a comprehensive comparative analysis of gene duplication between <T. gondii> and its close relatives <Neospora caninum> and <Hammondia hammondi>. We show that despite the high degree of synteny between these species, they differ significantly in their expanded gene profiles. Interestingly, we find that these expanded loci (EL) are under strong diversifying selection and that many exhibit copy-number variations among different strains of the same species. Additionally, we have performed functional analyses on two expanded loci: we have identified EL4 to be responsible for host mitochondrial association, which is a trait unique to <T. gondii>, and also shown that EL3 may be involved in regulating parasite proliferation during bradyzoite differentiation. Our results suggest that gene duplication may represent an important underlying distinction that sets <T. gondii> apart from its less pathogenic relatives such as <N. caninum> and <H. hammondi>.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Adomako-Ankomah, Yaw | yaa16@pitt.edu | YAA16 | |
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| ETD Committee: |
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| Date: |
28 January 2014 |
| Date Type: |
Publication |
| Defense Date: |
5 December 2013 |
| Approval Date: |
28 January 2014 |
| Submission Date: |
6 December 2013 |
| Access Restriction: |
1 year -- Restrict access to University of Pittsburgh for a period of 1 year. |
| Number of Pages: |
156 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Biological Sciences |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Toxoplasma gondii
Neospora caninum
Tandem gene-duplication |
| Date Deposited: |
28 Jan 2014 16:04 |
| Last Modified: |
15 Nov 2016 14:16 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/20240 |
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