Complex chromosomal neighborhood effects determine the adaptive potential of a gene under selection Steinrück, Magdalena ; https://orcid.org/0000-0003-1229-9719 Guet, Calin C ; https://orcid.org/0000-0001-6220-2052 ddc:576 How the organization of genes on a chromosome shapes adaptation is essential for understanding evolutionary paths. Here, we investigate how adaptation to rapidly increasing levels of antibiotic depends on the chromosomal neighborhood of a drug-resistance gene inserted at different positions of the Escherichia coli chromosome. Using a dual-fluorescence reporter that allows us to distinguish gene amplifications from other up-mutations, we track in real-time adaptive changes in expression of the drug-resistance gene. We find that the relative contribution of several mutation types differs systematically between loci due to properties of neighboring genes: essentiality, expression, orientation, termination, and presence of duplicates. These properties determine rate and fitness effects of gene amplification, deletions, and mutations compromising transcriptional termination. Thus, the adaptive potential of a gene under selection is a system-property with a complex genetic basis that is specific for each chromosomal locus, and it can be inferred from detailed functional and genomic data. eLife Sciences Publications 2017 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/704 https://research-explorer.ista.ac.at/download/704/4975 https://research-explorer.ista.ac.at/download/704/4976 Steinrück M, Guet CC. Complex chromosomal neighborhood effects determine the adaptive potential of a gene under selection. <i>eLife</i>. 2017;6. doi:<a href="https://doi.org/10.7554/eLife.25100">10.7554/eLife.25100</a> eng info:eu-repo/semantics/altIdentifier/doi/10.7554/eLife.25100 info:eu-repo/semantics/altIdentifier/issn/2050-084X info:eu-repo/semantics/altIdentifier/wos/000406183700001 https://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess