Twenty-five years and over 50,000 bacterial generations ago, one of the longest open-ended experiments in modern times began when the Lenski laboratory started passaging Escherichia coli under conditions of limited glucose as a carbon source [1]. Later that same year, a paper was published describing a new method for DNA sequencing, called pyrosequencing, that would ultimately light a path towa...

We revisit the model by Wiser, Ribeck, and Lenski (Science 342 (2013), 1364–1367), which describes how the mean fitness increases over time due to beneficial mutations in Lenski’s long-term evolution experiment. We develop the model further both conceptually and mathematically. Conceptually, we describe the experiment with the help of a Cannings model with mutation and selection, where the latt...

Evolutionary innovations that enable organisms to colonize new ecological niches are rare compared to gradual evolutionary changes in existing traits. We discovered that key mutations in the gltA gene, which encodes citrate synthase (CS), occurred both before and after Escherichia coli gained the ability to grow aerobically on citrate (Cit(+) phenotype) during the Lenski long-term evolution exp...

More than a century ago, Theodor Escherich isolated the bacterium that was to become Escherichia coli, one of the most studied organisms. Not long after, the strain began an odyssey and landed in many laboratories across the world. As laboratory culture conditions could be responsible for major changes in bacterial strains, we conducted a genome analysis of isolates of this emblematic strain fr...

This study is examining the relationship between the rate of religiousity and attitude toward democracy in Nayshabor citizens. To do so, a survey was done in a sample of 295 literate citizens were selected in PPS method. Theoretical framework is selected according to the theories of Lenski, Weber and Cultural wars theory and religiosity measurement is done according to Glock and Stark’s multidi...

The evolutionary stability of sexual reproduction requires advantages sufficient to overcome the substantial costs of cross-fertilization (Williams, 1975; Maynard Smith, 1978; Bell, 1982; Lively & Lloyd, 1990). Such advantages have been sought primarily among those known to be associated with the production of variable offspring (but see Bernstein et al., 1985). Of those considered, two advanta...

estimation of speciation and extinction rates, ancestral character states, and rates of anagenetic and cladogenetic evolution on a molecular phylogeny. Evolution 62, 2718–2726 4 Webster, A.J. et al. (2003) Molecular phylogenies link rates of evolution and speciation. Science 301, 478 5 Pagel, M. et al. (2006) Large punctuational contribution of speciation to evolutionary divergence at the molec...

The Long Time Evolution Experiment. I recall the extremely interesting experiment with E. Coli, conducted by Prof. R. Lenski and his group [1, 2], and running already for more than 27 years. Among the reported results, I use the following [3]: 1. In a culture of bacteria, after 20,000 generations, around 3 × 10 single point mutations in the DNA are registered. These are local modifications of t...