The Unconventionality of Nature: Biology, from Noise to Functional Randomness

Abstract

In biology, phenotypes' variability stems from stochastic gene expression as well as from intrinsic and extrinsic fluctuations that are largely based on the contingency of evolutionary and developmental paths and on ecosystemic changes. Both forms of randomness constructively contribute to biological robustness, as resilience, far away from conventional computable dynamics, where elaboration and transmission of information are robust when they resist to noise. We first survey how fluctuations may be inserted in biochemical equations as probabilistic terms, in conjunction to diffusion or path integrals, and treated by statistical approaches to physics. Further work allows to better grasp the role of biological "resonance" (interactions between different levels of organization) and plasticity, in a highly unconventional frame that seems more suitable for biological processes. In contrast to physical conservation properties, thus symmetries, symmetry breaking is particularly relevant in biology; it provides another key component of biological historicity and of randomness as a source of diversity and, thus, of onto-phylogenetic stability and organization as these are also based on variation and adaptativity.

Noise and Synthetic Biology: How to Deal with Stochasticity?

“…The "Information Metaphor Falsehood" and the Glorification of Noise Both the field of epistemology [28,39,40] as well as philosophy of biology [16][17][18]41] have recently raised concerns about the dominance of reductionism in the field of biology, and in particular biological engineering. Stressing as well a problem of nomenclature, when from these disciplines, we see examples of what is called noise that in fact might be randomness playing a positive role for an organism.…”

“…According to Longo [16], a system is robust when it resists noise. This is particularly true of living systems, where randomness has a functional role that contributes (in an essential way) to the structural stability of system dynamics.…”

“…Longo understands that noise refers to small (and frequent) fluctuations (2018) in general, which may actually disturb the achieved stability of a biological system. He argues that we should not call these intrinsically random aspects of onto-phylogenesis [16] noise, but rather consider them indispensable components of stable biological complexity. For him, randomness is so intrinsic to the evolutionary stability of those systems that it can be argued there is no noise for such systems.…”

“…In the last decade there have been remarkable efforts challenging the problematic misconceptualisation of chance and noise in the form of random fluctuations and perturbations (e.g. [16][17][18]; or [19]). 2 In what follows, we will cover their progress as we need to provide another account of the phenomenon of noise as it enters a system in many different structural-functional configurations.…”

Gravity Constraints Drive Biological Systems Toward Specific Organization Patterns

“…Bravi and Longo gave a very clear definition of the kind of action that gravity exerts on development in terms of “canalization by constraints”: “gravity constrains development : typically, it canalizes cytoskeletal growth toward relatively flat structures as well as selecting negatively shapes that are unsuitable for subsistence or movement. When the constraint is reduced or disappears, descent with modification yields a larger variety of enabled structures.…”