Month: September 2022

EXPLOITING NOISE. “Many systems for specifying the polarity of cells or groups of cells rely on a mechanism known as ‘lateral inhibition’, which causes adjacent cells to follow different fates. This process can amplify a small, often stochastic, initial asymmetry causing adjacent cells or adjacent areas within cells to follow different fates.” https://www.nature.com/articles/35011540 View in LinkedIn

NOVEL DEVICES IN BIOLOGY. “Other aspects of functional modules are less familiar to engineers. Several can be subsumed under the idea that the rules for a module's function are rigidly encoded in the structures of its proteins, but produce messy, probabilistic intermediates that are then refined to give unique solutions. This principle seems to hold across an enormous range of scales, from the folding of protein molecules to the evolution of organisms.” https://www.nature.com/articles/35011540 View in LinkedIn

COMBINED RIGIDITY AND MESSINESS. “The principle arises from a combination of three mechanisms: exploration with selection (trial and error), error-correction mechanisms, and error-detection modules that delay subsequent events until a process has been successfully completed. These are present to different extents in different examples.” https://www.nature.com/articles/35011540 View in LinkedIn

UNTANGLING THE PRESENT BY THE PAST. “Today's organisms have an unbroken chain of ancestors stretching back to the origin of life. This constraint has been successfully used to understand protein functions, by comparing existing protein sequences from related species, finding conserved parts and inferring their roles. Comparing modules of common function from different organisms should be a similarly useful tool for understanding their operation.” https://www.nature.com/articles/35011540 View in LinkedIn

CRITICAL ROBUSTNESS. “The survival of living systems implies that the critical parameters of essential modules, such as the accuracy of chromosome segregation or the periodicity of a circadian clock, are robust: they are insensitive to many environmental and genetic perturbations.” https://www.nature.com/articles/35011540 View in LinkedIn

CRITICAL PLASTICITY. “Evolvability, on the other hand, requires that other parameters of modules are sensitive to genetic changes. They can then be modified over many generations to alter the function of a module, or its connections to other modules, in a way that allows organisms to adapt to new challenges. It is important to understand how robustness and flexibility can be reconciled for each functional module.” https://www.nature.com/articles/35011540 View in LinkedIn

THE TWO EXTREMES. “Organisms have been selected for two properties: rapid reproduction in optimal conditions and the ability to survive rarely encountered extreme conditions. Because environments tend to fluctuate over time, most modules are likely to have been selected for their ability to contribute to both reproduction and survival.” https://www.nature.com/articles/35011540 View in LinkedIn

THE SELFISH GENE. “Survival of a gene pool, as opposed to an individual organism, is favoured by diversification, as the simultaneous presence of multiple phenotypes in a population increases the possibility that some individuals will survive and reproduce in a heterogeneous and changing environment.” https://www.nature.com/articles/35011540 View in LinkedIn

GENE POOL DIVERSITY. “Diversification can be achieved by epigenetic mechanisms that enable a single genotype to produce more than one phenotype, by genetic mechanisms that maintain multiple genotypes in a population, and by speciation, which splits a single gene pool into two independently evolving pools.” https://www.nature.com/articles/35011540 View in LinkedIn