The laboratory domestication of Caenorhabditis elegans

• Laboratory-derived alleles in the Caenorhabditis elegans reference strain Bristol N2 cause large phenotypic effects.
• These alleles were selected after many generations of growth in the laboratory.
• Natural strains are more representative of C. elegans behaviors and physiology than the laboratory strain N2.

Model organisms are of great importance to our understanding of basic biology and to making advances in biomedical research. However, the influence of laboratory cultivation on these organisms is underappreciated, and especially how that environment can affect research outcomes. Recent experiments led to insights into how the widely used laboratory reference strain of the nematode Caenorhabditis elegans compares with natural strains. Here we describe potential selective pressures that led to the fixation of laboratory-derived alleles for the genes npr-1, glb-5, and nath-10. These alleles influence a large number of traits, resulting in behaviors that affect experimental interpretations. Furthermore, strong phenotypic effects caused by these laboratory-derived alleles hinder the discovery of natural alleles. We highlight strategies to reduce the influence of laboratory-derived alleles and to harness the full power of C. elegans.