@article {Yona111880, author = {Avihu H. Yona and Eric J. Alm and Jeff Gore}, title = {Random Sequences Rapidly Evolve into de novo Promoters}, elocation-id = {111880}, year = {2017}, doi = {10.1101/111880}, publisher = {Cold Spring Harbor Laboratory}, abstract = {How do new promoters evolve? The current notion is that new promoters emerge from duplication of existing promoters. To test whether promoters can instead evolve de novo, we replaced the lac promoter of Escherichia coli with various random sequences and evolved the cells in the presence of lactose. We found that a typical random sequence of \~{}100 bases requires only one mutation in order to mimic the canonical promoter and to enable growth on lactose. We further found that \~{}10\% of random sequences could serve as active promoters even without any period of evolutionary adaptation. Such a short mutational distance from a random sequence to an active promoter may improve evolvability yet may also lead to undesirable accidental expression. Nevertheless, we found that across the E. coli genome, accidental expression is largely avoided by disfavoring codon combinations that resemble canonical promoter motifs. Our results suggest that the promoter recognition machinery has been tuned to allow high accessibility to new promoters, and similar findings might also be observed in higher organisms or in other motif recognition machineries, like transcription factor binding sites or protein-protein interactions.}, URL = {https://www.biorxiv.org/content/early/2017/05/19/111880}, eprint = {https://www.biorxiv.org/content/early/2017/05/19/111880.full.pdf}, journal = {bioRxiv} }