David Krakauer | PubMed Health

PubMed2003

Perspective: Evolution and detection of genetic robustness.

Robustness is the invariance of phenotypes in the face of perturbation. The robustness of phenotypes appears at various levels of biological organization, including gene expression, protein folding, metabolic flux, physiological homeostasis, development, and even organismal fitness. The mechanisms underlying robustness are diverse, ranging from thermodynamic stability at the RNA and protein level to behavior at the organismal level. Phenotypes can be robust either against heritable perturbations (e.g., mutations) or nonheritable perturbations (e.g., the weather). Here we primarily focus on the first kind of robustness--genetic robustness--and survey three growing avenues of research: (1) measuring genetic robustness in nature and in the laboratory; (2) understanding the evolution of genetic robustness: and (3) exploring the implications of genetic robustness for future evolution.

Adaptation, Biological↗

PubMed2002

From physics to phenomenology. Levels of description and levels of selection.

Formal models in biology are traditionally of two types: simulation models in which individual components are described in detail with extensive empirical support for parameters, and phenomenological models, in which collective behaviour is described in the hope of identifying critical variables and parameters. The advantage of simulation is greater realism but at a cost of limited tractability, whereas the advantage of phenomenological models, is greater tractability and insight but at a cost of reduced predictive power. Simulation models and phenomenological models lie on a continuum, with phenomenological models being a limiting case of simulation models. I survey these two levels of model description in genetics, molecular biology, immunology and ecology. I suggest that evolutionary considerations of the levels of selection provides an important justification for many phenomenological models. In effect, evolution reduces the dimension of biological systems by promoting common paths towards increased fitness.

Animals↗