Degeneracy allows for both apparent homogeneity and diversification in populations

Abstract

Trait diversity – the substrate for natural selection – is necessary for adaptation through selection, particularly in populations faced with environmental changes that diminish population fitness. In habitats that remain unchanged for many generations, stabilizing selection maximizes exploitation of resources by reducing trait diversity to a narrow optimal range. One might expect that such ostensibly homogeneous populations would have a reduced potential for heritable adaptive responses when faced with fitness-reducing environmental changes. However, field studies have documented populations that, even after long periods of evolutionary stasis, can still rapidly evolve in response to changed environmental conditions. We argue that degeneracy, the ability of diverse population elements to function similarly, can satisfy both the current need to maximize fitness and the future need for diversity. Degenerate ensembles appear functionally redundant in certain environmental contexts and functionally diverse in others. We propose that genetic variation not contributing to the observed range of phenotypes in a current population, also known as cryptic genetic variation (CGV), is a specific case of degeneracy. We argue that CGV, which gradually accumulates in static populations in stable environments, reveals hidden trait differences when environments change. By allowing CGV accumulation, static populations prepare themselves for future rapid adaptations to environmental novelty. A greater appreciation of degeneracy’s role in resolving the inherent tension between current stabilizing selection and future directional selection has implications in conservation biology and may be applied in social and technological systems to maximize current performance while strengthening the potential for future changes.

Non-local competition drives both rapid divergence and prolonged stasis in a model of speciation in populations with degenerate resource consumption

“…Populations with mixed, heritably retained degeneracy ranges (narrow, intermediate, and broad) need to be tested to better approximate real-world populations. As a theoretical exercise and in preparation for the degeneracy-driven technologies of the future [38], it would be interesting to assess the possibility that individual degeneracy ranges vary in time, stochastically or depending on current fitness. In the implementation presented in the current study, trait degeneracy was intrinsic to individuals and had no cost to them, whereas in some realistic populations, broader degeneracy may come at a higher individual or systemic cost, and must be considered as explorative behavior.…”

Epigenomics and the concept of degeneracy in biological systems

“…Degeneracy is a distributed property of complex adaptive systems that in many circles of science has been hidden in plain sight [ 4 ], commonly overlooked because of a reductionist bias [ 5 , 6 ], and ignored because the term itself is misleading [ 7 ]. Although degeneracy is known to be a characteristic of genetic codes [ 8 , 9 ], immune systems [ 10 ], respiratory network regulation of blood-gas homoeostasis [ 11 ], human movement [ 12 , 13 ], cognitive neuroanatomy [ 14–16 ], population dynamics [ 17 , 18 ], and as a conceptual tool offered the final solution to the coding problem of DNA [ 19 ], the term is still not well comprehended in evolutionary biology.…”

Systematic Measures of Biological Networks II: Degeneracy, Complexity, and Robustness

“…Many simulations and experiments have already suggested that there are close connections among degeneracy, complexity and robustness in a biological system (see e.g. [7,10,29,32,33]). For the evolutionary network (1.1) and its noise perturbation (1.2), we will rigorously show the following results under the conditions H 0 ) and H 1 ) :…”