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Mutation and epimutation load in haploid and diploid life forms.
Hans K Stenøien1, Bård Pedersen
1Plant Ecology/Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Villav. 14, Uppsala, SE-752 36, Sweden. hans.stenoien@ebc.uu.se
Journal of Theoretical Biology
|December 24, 2004
Summary
Epigenetic changes (epimutations) can impact gene expression and have fitness consequences similar to mutations. Their effects depend on rate, reversibility, and inheritance, potentially influencing organismal complexity.
Area of Science:
- Genetics
- Evolutionary Biology
- Epigenetics
Background:
- Epigenetic differentiation involves heritable gene expression changes without altering DNA sequence.
- Understanding epimutations is crucial for analyzing genetic load and evolutionary processes.
Purpose of the Study:
- Introduce a classification scheme for mutations and epimutations.
- Analyze the fitness consequences of epimutations in different inheritance contexts.
- Explore the role of epimutations in organismal evolution, including somatic inheritance and diploidy.
Main Methods:
- Developed a classification system for mutations and epimutations.
- Analyzed mutation and epimutation load in haploid and diploid organisms.
- Modeled fitness consequences based on epimutation rate, reversibility, and inheritance.
Main Results:
- Deleterious effects of epimutations are primarily driven by their rate and reversibility.
- Inherited epimutations have fitness consequences comparable to inherited mutations.
- Epimutations with complete reversibility and no inheritance mirror somatic mutations' effects.
Conclusions:
- Organisms with somatic inheritance may face higher genetic loads due to inherited epimutations.
- Inherited epimutations may partly explain the evolution of soma/germ line differentiation.
- The masking of somatic mutations might not solely explain the evolution of diploidy in the presence of inherited epimutations.