Regulating Evolvability and Robustness under Environmental Variability

Posma, Anke (2023) Regulating Evolvability and Robustness under Environmental Variability. Master's Thesis / Essay, Ecology and Evolution.

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Abstract

Life has evolved the ability to be both robust, as well as adaptable to environmental changes. Shaping the genotype-phenotype-fitness mapping, environmental variability can open up evolutionary paths. Here, the effects of a variable environment on evolvability and robustness at different levels of complexity are discussed using the architecture of gene regulatory networks. At the lowest level of complexity - direct interactions - mutational trajectories can become accessible under environmental fluctuations. Additionally, hierarchical structuring within initiation complexes can promote evolvability and robustness. At the intermediate level of complexity, evolvability and robustness is mainly due to promiscuous binding of transcription factors. The chance of promiscuous binding can be achieved by increased transcription factor levels. These newly established connections allow for control over novel downstream effectors. Lastly, the entanglement of networks exhibits high evolvability and robustness at the highest level of complexity. This entanglement is essentially a combination of hierarchical clustering and promiscuous binding. A variable environment can therefore overcome evolutionary constraints, by affecting the expressed phenotype, as well as oppose constraints, by defining the selective forces. However, the general trend suggests that an increasing level of complexity coincides with smaller environmental effects, as robustness and evolvability grow with complexity.

Item Type:	Thesis (Master's Thesis / Essay)
Supervisor name:	Vos, M.G.J. de
Degree programme:	Ecology and Evolution
Thesis type:	Master's Thesis / Essay
Language:	English
Date Deposited:	20 Nov 2023 11:26
Last Modified:	20 Nov 2023 11:26
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/31656

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