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PROVING GROUND. “The evolution of new metabolic capabilities was studied in several early experiments with microorganisms. These organisms often gained the ability to use new compounds as nutrient sources by successive mutations in genes that activated their transcription under new conditions, increased their overall expression levels or altered their substrate specificities.” https://www.nature.com/articles/nrg3564 View in LinkedIn

SINGLE MUTATIONS. “It is also likely that some examples of yeast that evolved a new multicellular 'snowflake' phenotype needed only single adaptive mutations.” https://www.nature.com/articles/nrg3564 View in LinkedIn

HUGELY IMPORTANT. “Some experiments have observed qualitatively new, often 'game-changing' abilities that have the hallmarks of evolutionary innovations. Some innovations may require only a single mutation.” https://lnkd.in/dndws4D5 View in LinkedIn

FITNESS LANDSCAPE. “In particular, prior mutational steps in a path on the fitness landscape may affect evolvability in at least two main ways. They may alter mutation rates (and/or recombination rates for organisms that are capable of sexual reproduction or horizontal gene transfer), or they may lead to differences in epistatic interactions with potential further mutations.” https://www.nature.com/articles/nrg3564 View in LinkedIn

PLANT BACTERIA. “The experimentally evolved transition of a chimeric Ralstonia solanacearum strain from a plant pathogen into a symbiont that is able to colonize root nodules also required only a single mutation in hrpG, which encodes a protein that regulates the expression of several virulence factors.” https://www.nature.com/articles/nrg3564 View in LinkedIn

TOOLBOX. “When there is genetic diversity in evolving populations for long periods of time, there is the opportunity for selection to operate not only on the immediate effects of mutations or new combinations of alleles but also on how those new genotypes differ in their capability to further evolve (that is, their evolvability).” https://www.nature.com/articles/nrg3564 View in LinkedIn

BACTERIAL SURPRISE. “That key mutation did not revert any of the previous mutations but occurred instead in a previously uncharacterized small RNA.” https://www.nature.com/articles/nrg3564 View in LinkedIn

THE STRESS LEVER. “Stressful environments can sometimes help to separate the more beneficial mutations from the less beneficial mutations.” https://www.nature.com/articles/nrg3564 View in LinkedIn

BACTERIAL EXAMPLE. “For example, whole-genome sequencing of experimentally evolved Myxococcus xanthus strains found that 14 mutations were substituted after 1,000 generations in a liquid medium, while social motility and the capability to form fruiting bodies were lost, but only one mutation was involved in the subsequent restoration of those functions.” https://www.nature.com/articles/nrg3564 View in LinkedIn

MANY PATHWAYS. “Indeed, divergent paths have been described in most evolution experiments with microorganisms, and these dynamics have been reconstructed in certain cases.” https://www.nature.com/articles/nrg3564 View in LinkedIn