Michael OLeary
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PhD Title
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Investigating Biological Insurance: Identifying the use of bet-hedging as an evolutionary strategy to adapt to unpredictable and rapidly fluctuating environmental conditions. |
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Research Theme
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Evolution and Adaptation |
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Primary Supervisor
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Primary Institution
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Secondary Supervisor
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Secondary Institution
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Abstract
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There are three known strategies of evolutionary adaptation to environmental change. The first involves adapting directly to changed environmental conditions via natural selection (adaptive tracking), and the second is via evolution of physiological developmental mechanisms that can accommodate detectable or predictable changes (phenotypic plasticity). However, these strategies fail when the environmental change is too rapid or too novel. This is when a population that uses bet-hedging might do better. A bet-hedger will sacrifice short term fitness in its current environmental conditions by producing offspring that are better adapted to possible future environmental conditions. This spreads risk amongst its offspring ensuring that at least some will survive. Bet-hedging maximises geometric mean fitness in unpredictable environments, at the expense of arithmetic mean fitness. Adaptive bet-hedging is well supported by theory but is challenging to demonstrate empirically. We will overcome this by experimentally evolving large populations of fast-growing yeast. Chromosome mis-segregation provides a mechanism for reversible phenotypic switches between toxin-resistant but slow-growing aneuploid offspring and fast growing but toxin-sensitive euploid cells. We will be genetically manipulating chromosome mis-segregation rates and identify long and short-term fitness effects in environments with different regimes of toxin presence/absence fluctuation. |
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Policy Impact
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Background Reading
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Publications
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None |
