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EXPERIMENTAL STRESS. “An important 'dial' that can be adjusted in experimental evolution studies is the strength of selection, particularly if the goal is to improve some phenotypic property. In one limit, selection may be so strong that it becomes a genetic screen in which only rare mutants with extreme, perhaps innovative, phenotypes can survive the stress (Fig. 2c).” https://www.nature.com/articles/nrg3564 View in LinkedIn

CONFOUNDER. “The earlier potentiating mutations did not confer any immediate advantage with respect to using citrate, but they may have been beneficial with respect to growth on glucose. If so, it is possible that other populations in the LTEE have also become potentiated and might evolve the Cit+ phenotype, although no others have done so even after >50,000 generations.” https://www.nature.com/articles/nrg3564 View in LinkedIn

MECHANICS OF THE ADAPTATION. “The key actualizing mutation arose by a chromosomal duplication event that 'rewired' gene expression by placing a new transcriptional promoter upstream of a previously silent citrate transporter gene to give the Cit+ phenotype (that is, the ability to use citrate as a nutrient source).” https://www.nature.com/articles/nrg3564 View in LinkedIn

BACTERIAL OLYMPICS. “This innovation was difficult because it was contingent on one or more earlier 'potentiating' mutations that had to be present in the genetic background for the key 'actualizing' mutation to establish in the population.” https://www.nature.com/articles/nrg3564 View in LinkedIn

Seeing inside living cells with the external context, a huge jump forward in microscopy. https://youtu.be/FHJo_eQPOG8 View in LinkedIn

“THE STUFF which the world of our experience is composed is, in my belief, neither mind nor matter but something more primitive than either. Both mind and matter seem to be a composite, and the stuff of which they are compounded lis in a sense between the two, in a sense above them both, like a common ancestor.” (Bertrand Russell, 1921). https://lnkd.in/dGjr7B9y View in LinkedIn

NEW NUTRIENT USE. “The LTEE uses a glucose-limited medium, but citrate — another nutrient that E. coli generally cannot use — has also been present throughout the experiment. The ability to use this abundant but untapped resource evolved after 30,000 generations (~15 years) and in only one of the 12 replicate populations.” https://www.nature.com/articles/nrg3564 View in LinkedIn

MIXED MUTATIONS. “In these examples, the relevant mutations each conferred a direct advantage in terms of using the new resource, but this need not be the case.” https://www.nature.com/articles/nrg3564 View in LinkedIn

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