Evolvability

About: Evolvability is a research topic. Over the lifetime, 1363 publications have been published within this topic receiving 57385 citations.

Biological robustness

Abstract: Robustness is a ubiquitously observed property of biological systems. It is considered to be a fundamental feature of complex evolvable systems. It is attained by several underlying principles that are universal to both biological organisms and sophisticated engineering systems. Robustness facilitates evolvability and robust traits are often selected by evolution. Such a mutually beneficial process is made possible by specific architectural features observed in robust systems. But there are trade-offs between robustness, fragility, performance and resource demands, which explain system behaviour, including the patterns of failure. Insights into inherent properties of robust systems will provide us with a better understanding of complex diseases and a guiding principle for therapy design.

Perspective: complex adaptations and the evolution of evolvability

Abstract: The problem of complex adaptations is studied in two largely disconnected research traditions: evolutionary biology and evolutionary computer science. This paper summarizes the results from both areas and compares their implications. In evolutionary computer science it was found that the Darwinian process of mutation, recombination and selection is not universally effective in improving complex systems like computer programs or chip designs. For adaptation to occur, these systems must possess "evolvability," i.e., the ability of random variations to sometimes produce improvement. It was found that evolvability critically depends on the way genetic variation maps onto phenotypic variation, an issue known as the representation problem. The genotype-phenotype map determines the variability of characters, which is the propensity to vary. Variability needs to be distinguished from variations, which are the actually realized differences between individuals. The genotype-phenotype map is the common theme underlying such varied biological phenomena as genetic canalization, developmental constraints, biological versatility, developmental dissociability, and morphological integration. For evolutionary biology the representation problem has important implications: how is it that extant species acquired a genotype-phenotype map which allows improvement by mutation and selection? Is the genotype-phenotype map able to change in evolution? What are the selective forces, if any, that shape the genotype-phenotype map? We propose that the genotype-phenotype map can evolve by two main routes: epistatic mutations, or the creation of new genes. A common result for organismic design is modularity. By modularity we mean a genotype-phenotype map in which there are few pleiotropic effects among characters serving different functions, with pleiotropic effects falling mainly among characters that are part of a single functional complex. Such a design is expected to improve evolvability by limiting the interference between the adaptation of different functions. Several population genetic models are reviewed that are intended to explain the evolutionary origin of a modular design. While our current knowledge is insufficient to assess the plausibility of these models, they form the beginning of a framework for understanding the evolution of the genotype-phenotype map.

Protein stability promotes evolvability.

Abstract: The biophysical properties that enable proteins to so readily evolve to perform diverse biochemical tasks are largely unknown. Here, we show that a protein’s capacity to evolve is enhanced by the mutational robustness conferred by extra stability. We use simulations with model lattice proteins to demonstrate how extra stability increases evolvability by allowing a protein to accept a wider range of beneficial mutations while still folding to its native structure. We confirm this view experimentally by mutating marginally stable and thermostable variants of cytochrome P450 BM3. Mutants of the stabilized parent were more likely to exhibit new or improved functions. Only the stabilized P450 parent could tolerate the highly destabilizing mutations needed to confer novel activities such as hydroxylating the antiinflammatory drug naproxen. Our work establishes a crucial link between protein stability and evolution. We show that we can exploit this link to discover protein functions, and we suggest how natural evolution might do the same.

Animal personalities: consequences for ecology and evolution

Abstract: Personality differences are a widespread phenomenon throughout the animal kingdom. Past research has focused on the characterization of such differences and a quest for their proximate and ultimate causation. However, the consequences of these differences for ecology and evolution received much less attention. Here, we strive to fill this gap by providing a comprehensive inventory of the potential implications of personality differences, ranging from population growth and persistence to species interactions and community dynamics, and covering issues such as social evolution, the speed of evolution, evolvability, and speciation. The emerging picture strongly suggests that personality differences matter for ecological and evolutionary processes (and their interaction) and, thus, should be considered a key dimension of ecologically and evolutionarily relevant intraspecific variation.

Robustness and Evolvability in Living Systems

Abstract: List of Figures ix Acknowledgments xiii Chapter 1: Introduction 1 PART I: ROBUSTNESS BELOW THE GENE LEVEL 13 Chapter 2: The Genetic Alphabet 15 Chapter 3: The Genetic Code 25 Chapter 4: RNA Structure 39 Chapter 5: Proteins and Point Mutations 62 Chapter 6: Proteins and Recombination 78 PART II: ROBUSTNESS ABOVE THE GENE LEVEL 91 Chapter 7: Regulatory DNA Regions and Their Reorganization in Evolution 93 Chapter 8: Metabolic Pathways 104 Chapter 9: Metabolic Networks 120 Chapter 10: Drosophila Segmentation and Other Gene Regulatory Networks 143 Chapter 11: Phenotypic Traits, Cryptic Variation, and Human Diseases 161 Chapter 12: The Many Ways of Building the Same Body 175 PART III: COMMON PRINCIPLES 193 Chapter 13: Neutral Spaces 195 Chapter 14: Evolvability and Neutral Mutations 217 Chapter 15: Redundancy of Parts or Distributed Robustness? 228 Chapter 16: Robustness as an Evolved Adaptation to Mutations 247 Chapter 17: Robustness as an Evolved Adaptation to Environmental Change and Noise 270 Chapter 18: Robustness and Fragility: Advantages to Variation and Trade-offs 281 PART IV: ROBUSTNESS BEYOND THE ORGANISM 295 Chapter 19: Robustness in Natural Systems and Self-Organization 297 Chapter 20: Robustness in Man-made Systems 310 Epilogue: Seven Open Questions for Systems Biology 321 Bibliography 323 Index 359