Full metadata
Title
A practical and theoretical approach to understanding the selective mechanisms behind genetic caste determination in Pogonomyrmex rugosus and Pogonomyrmex barbatus
Description
Gene-centric theories of evolution by natural selection have been popularized and remain generally accepted in both scientific and public paradigms. While gene-centrism is certainly parsimonious, its explanations fall short of describing two patterns of evolutionary and social phenomena: the evolution of sex and the evolution of social altruism. I review and analyze current theories on the evolution of sex. I then introduce the conflict presented to gene-centric evolution by social phenomena such as altruism and caste sterility in eusocial insects. I review gene-centric models of inclusive fitness and kin selection proposed by Hamilton and Maynard Smith. Based their assumptions, that relatedness should be equal between sterile workers and reproductives, I present several empirical examples that conflict with their models. Following that, I introduce a unique system of genetic caste determination (GCD) observed in hybrid populations of two sister-species of seed harvester ants, Pogonomyrmex rugosus and Pogonomyrmex barbatus. I review the evidence for GCD in those species, followed by a critique of the current gene-centric models used to explain it. In chapter two I present my own theoretical model that is both simple and extricable in nature to explain the origin, evolution, and maintenance of GCD in Pogonomyrmex. Furthermore, I use that model to fill in the gaps left behind by the contributing authors of the other GCD models. As both populations in my study system formed from inter-specific hybridization, I review modern discussions of heterosis (also called hybrid vigor) and use those to help explain the ecological competitiveness of GCD. I empirically address the inbreeding depression the lineages of GCD must overcome in order to remain ecologically stable, demonstrating that as a result of their unique system of caste determination, GCD lineages have elevated recombination frequencies. I summarize and conclude with an argument for why GCD evolved under selective mechanisms which cannot be considered gene-centric, providing evidence that natural selection can effectively operate on non-heritable genotypes appearing in groups and other social contexts.
Date Created
2012
Contributors
- Jacobson, Neal (Author)
- Gadau, Juergen (Thesis advisor)
- Laubichler, Manfred (Committee member)
- Pratt, Stephen (Committee member)
- Arizona State University (Publisher)
Topical Subject
- Biology
- Evolution & development
- Genetics
- Dependent Lineage
- Genetic Caste Determination
- Model
- Natural selection
- Pogonomyrmex barbatus
- Pogonomyrmex rugosus
- Rough harvester ant--Genetics.
- Rough harvester ant
- Rough harvester ant--Evolution.
- Rough harvester ant
- Rough harvester ant--Behavior.
- Rough harvester ant
Resource Type
Extent
viii, 100 p. : ill. (some col.)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.14939
Statement of Responsibility
by Neal Jacobson
Description Source
Retrieved on April 29, 2013
Level of coding
full
Note
thesis
Partial requirement for: M.S., Arizona State University, 2012
bibliography
Includes bibliographical references (p. 94-100)
Field of study: Biology
System Created
- 2012-08-24 06:26:12
System Modified
- 2021-08-30 01:46:31
- 3 years 2 months ago
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