Our genes (aka. the genotype) determine our characteristics (aka. the phenotype). Evolution acts on changes in the phenotype, which occur when mutations change the underlying genotype. But what changes to the phenotype can be produced by mutations is not without bounds—ants cannot suddenly grow trunks or become the size of an elephant. Researchers at the Institute of Science and Technology Austria (IST Austria) found that in a gene regulatory system in the bacterium Escherichia coli, the more components that are mutated, the more freely the system can evolve. This is the result of a study published by a team led by Calin Guet, Jonathan Bollback, and first author Mato Lagator in eLife.