Universität zu Köln

Willemsen, David (2020). Life history evolution in turquoise killifish. PhD thesis, Universität zu Köln.

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Abstract

The classical evolutionary theories of aging predict that aging has evolved as the byproduct of mutations with deleterious effects late in life, due to the decline in force of natural selection with age. To investigate how differences in late life history can evolve in natural populations, I made use of the naturally short-lived turquoise killifish (Nothobranchius furzeri). Natural populations of the turquoise killifish occur along an extreme aridity gradient in the African savannah. Populations along this aridity gradient show differences in late life history, but not in early life history. Using a population genetics approach, I investigated the evolution of differences in aging and lifespan of turquoise killifish populations. I therefore performed pooled sequencing on 118 individuals from three different locations along the aridity gradient. Additionally, to investigate population demographic history, I performed high-coverage individual resequencing. I discovered that genes involved in mitochondrial and ribosomal functions have exceptionally low genetic divergence between all turquoise killifish population, indicating an important role in turquoise killifish biology. Furthermore, I found that the population from the most arid region, associated with a shorter lifespan and more accelerated aging, had a smaller recent and ancestral effective population size, relaxed natural selection and a higher level of deleterious mutations, especially in genes associated with aging and age-related disease pathways. My findings highlight the importance of demography in driving the evolution of late life history differences in natural populations, demonstrate that the evolution of these differences is consistent with the predictions of the classical evolutionary theories of aging, and connect these theories to the nearly neutral theory of molecular evolution. This work highlights the importance of relaxed selection in the context of molecular and phenotypic evolution.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Willemsen, David DWillemsen@age.mpg.de UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-106954
Date:	February 2020
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Außeruniversitäre Forschungseinrichtungen > MPI for Biology of Ageing
Subjects:	Life sciences
Uncontrolled Keywords:	Keywords Language Life history evolution English Turquoise killifish English Population genetics English
Date of oral exam:	6 June 2019
Referee:	Name Academic Title Valenzano, Dario R. Dr. Wiehe, Thomas Prof. Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/10695