Fundamental Properties of the Evolution of Mutational Robustness

Altenberg, Lee

doi:10.48550/arxiv.1508.07866

Cited by 4 publications

(5 citation statements)

References 37 publications

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“…This highlights that the "neutral evolution of mutational robustness" is not simply the evolutionary advantage of robust genotypes-it is a selection principle, which singles out, on a logarithmic scale, a subset of robust (e.g., BAYS) and nonrobust (e.g., WHYS) genotypes that are globally well connected in G. These patterns generalize to words of different lengths (Table 1 and fig. S4) and conform to a recent observation of Altenberg (23).…”

Section: Revisiting Maynard Smith's Four-letter Modelsupporting

confidence: 91%

“…Mutational robustness is normally defined as the fraction of functional one-point mutants of a genotype, but the results in (10)(11)(12) show that neutral quasispecies dynamics maximizes a different property: The most frequent genotypes at mutation-selection equilibrium are the ones with the largest eigenvector centrality in the neutral network. Eigenvector centrality is associated with not only high neutral degrees but also high assortativity (22) and cannot be assessed solely from the fitness of one-step mutants of a genotype-it is a nonlocal property, which depends on the structure of the whole neutral network (23).…”

Section: Introductionmentioning

confidence: 99%

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Neutral quasispecies evolution and the maximal entropy random walk

Smerlak

2021

Sci. Adv.

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Even if they have no impact on phenotype, neutral mutations are not equivalent in the eyes of evolution: A robust neutral variant—one which remains functional after further mutations—is more likely to spread in a large, diverse population than a fragile one. Quasispecies theory shows that the equilibrium frequency of a genotype is proportional to its eigenvector centrality in the neutral network. This paper explores the link between the selection for mutational robustness and the navigability of neutral networks. I show that sequences of neutral mutations follow a “maximal entropy random walk,” a canonical Markov chain on graphs with nonlocal, nondiffusive dynamics. I revisit M. Smith’s word-game model of evolution in this light, finding that the likelihood of certain sequences of substitutions can decrease with the population size. These counterintuitive results underscore the fertility of the interface between evolutionary dynamics, information theory, and physics.

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Section: Revisiting Maynard Smith's Four-letter Modelsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Neutral quasispecies evolution and the maximal entropy random walk

Smerlak

2021

Sci. Adv.

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“…For higher A this effect becomes more pronounced. As a possible biological application of the path graph the description of copy-number variants of genes can be mentioned [1]. Since the complete graph on two vertices without reversions has β * = 1 as shown before in (28) and adding edges can only decrease β * , it is actually required that the distance between a l and b l on the allele graph is at least 2 in order for β * > 1 to be possible.…”

Section: Path Graphmentioning

confidence: 99%

Accessibility Percolation on Cartesian Power Graphs

Schmiegelt¹,

Krug²

2019

Preprint

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A fitness landscape is a mapping from the space of genotypes to the real numbers. A path in a fitness landscape is a sequence of genotypes connected by single mutational steps. Such a path is said to be accessible if the fitness values of the genotypes encountered along the path increase monotonically. We study accessible paths on random fitness landscapes of the House-of-Cards type, which implies that the fitness values are independent, identically and continuously distributed random variables. The genotype space is taken to be a Cartesian power graph A L , where L is the number of genetic loci and the allele graph A encodes the possible allelic states and mutational transitions on one locus. The probability of existence of accessible paths between two genotypes at a distance linear in L displays a sharp transition from 0 to 1 at a threshold value β * of the fitness difference between the initial and final genotype. We derive a lower bound on β * for general A and conjecture that this bound is tight for a large class of allele graphs. Our results generalize previous results for accessibility percolation on the biallelic hypercube, and compare favorably to published numerical results for multiallelic Hamming graphs. A key tool of our analysis is the concept of quasi-accessibility, which eliminates the need to account for the self-avoidance of accessible paths.

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“…The nodes and leaves are labeled by continuous, independent and identically distributed (i.i.d.) random ¶ A possible biological interpretation of the linear mutation graph is that alleles represent copy-number variants of genes [2]. In this case the assignment of random fitness values is however not very plausible.…”

Section: Accessibility Percolation On Treesmentioning

confidence: 99%

Accessibility percolation in random fitness landscapes

Krug

2019

Preprint

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The fitness landscape encodes the mapping of genotypes to fitness and provides a succinct representation of possible trajectories followed by an evolving population. Evolutionary accessibility is quantified by the existence of fitnessmonotonic paths connecting far away genotypes. Studies of accessibility percolation use probabilistic fitness landscape models to explore the emergence of such paths as a function of the initial fitness, the parameters of the landscape or the structure of the genotype graph. This chapter reviews these studies and discusses their implications for the predictability of evolutionary processes.Determining the paths that evolution does not take is as important in evolutionary outcomes as shaping those it may pass through.

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Fundamental Properties of the Evolution of Mutational Robustness

Cited by 4 publications

References 37 publications

Neutral quasispecies evolution and the maximal entropy random walk

Neutral quasispecies evolution and the maximal entropy random walk

Accessibility Percolation on Cartesian Power Graphs

Accessibility percolation in random fitness landscapes

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