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Coevolutionary epidemiology : a population genetic exploration of evolutionary interactions between hosts and their infectious pathogens MacPherson, Ailene
Abstract
Coevolution between hosts and their parasites is widespread with important emergent consequences for natural systems from across the tree of life. The Red Queen Hypothesis suggests coevolution should maintain genetic variation in hosts and favour the evolution of sexual reproduction. Mathematical models have demonstrated that coevolutionary dynamics and the resulting effects on genetic variation and evolution of sex depend fundamentally on the genetic basis and life-history of the host-parasite interaction. Our understanding of the interaction genetics in natural systems is, however, still limited. In Chapter 2 I develop a statistical method based on genome-wide association studies (GWAS) to identify the genetic interactions between hosts and their parasites, demonstrating that inference of these genetic interactions is essential for a robust understanding of epidemiological traits. Classic models, including the one used in Chapter 2, consider the interaction between hosts and their free-living pathogens. Many pathogens are, however, directly transmitted between hosts and hence subject to epidemiological dynamics. In the Chapter 3, I consider the effects of these epidemiological dynamics on coevolution. We find, that epidemiological dynamics disrupt classic “Red Queen allele frequency cycles” observed in free-living pathogens, a change in dynamics that may limit the ability of coevolution to favour the evolution of sexual reproduction. Chapters 4 and 5 extend this by exploring the effects of epidemiological dynamics on the maintenance of genetic variation. Chapter 4 develops a baseline for the effect, examining the stochastic dynamics of heterozyogsity in a free-living pathogen population of constant size. In contrast to existing hypotheses, we find that coevolution in this classic model does not maintain genetic variation. In Chapter 5 we show that epidemiology can maintain genetic variation in hosts of directly transmitted pathogens, due in part to associated changes in population sizes. My thesis, therefore, demonstrates that, like other aspects of host and pathogen life-history, disease epidemiology fundamentally affects coevolutionary dynamics with implications for the evolution of sexual reproduction and the maintenance of genetic variation.
Item Metadata
Title |
Coevolutionary epidemiology : a population genetic exploration of evolutionary interactions between hosts and their infectious pathogens
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2020
|
Description |
Coevolution between hosts and their parasites is widespread with important emergent consequences for
natural systems from across the tree of life. The Red Queen Hypothesis suggests coevolution should maintain
genetic variation in hosts and favour the evolution of sexual reproduction. Mathematical models have
demonstrated that coevolutionary dynamics and the resulting effects on genetic variation and evolution of
sex depend fundamentally on the genetic basis and life-history of the host-parasite interaction. Our understanding
of the interaction genetics in natural systems is, however, still limited. In Chapter 2 I develop a
statistical method based on genome-wide association studies (GWAS) to identify the genetic interactions
between hosts and their parasites, demonstrating that inference of these genetic interactions is essential for a
robust understanding of epidemiological traits.
Classic models, including the one used in Chapter 2, consider the interaction between hosts and their
free-living pathogens. Many pathogens are, however, directly transmitted between hosts and hence subject
to epidemiological dynamics. In the Chapter 3, I consider the effects of these epidemiological dynamics on
coevolution. We find, that epidemiological dynamics disrupt classic “Red Queen allele frequency cycles”
observed in free-living pathogens, a change in dynamics that may limit the ability of coevolution to favour
the evolution of sexual reproduction. Chapters 4 and 5 extend this by exploring the effects of epidemiological
dynamics on the maintenance of genetic variation. Chapter 4 develops a baseline for the effect, examining
the stochastic dynamics of heterozyogsity in a free-living pathogen population of constant size. In contrast
to existing hypotheses, we find that coevolution in this classic model does not maintain genetic variation.
In Chapter 5 we show that epidemiology can maintain genetic variation in hosts of directly transmitted
pathogens, due in part to associated changes in population sizes. My thesis, therefore, demonstrates that, like
other aspects of host and pathogen life-history, disease epidemiology fundamentally affects coevolutionary
dynamics with implications for the evolution of sexual reproduction and the maintenance of genetic variation.
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Genre | |
Type | |
Language |
eng
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Date Available |
2020-04-02
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Provider |
Vancouver : University of British Columbia Library
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Rights |
Attribution-NonCommercial-NoDerivatives 4.0 International
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DOI |
10.14288/1.0389723
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2020-05
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Campus | |
Scholarly Level |
Graduate
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Rights URI | |
Aggregated Source Repository |
DSpace
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Rights
Attribution-NonCommercial-NoDerivatives 4.0 International