For geneticists working on model organisms, the job is all about linking genotype and phenotype. But nowadays, these researchers are facing a historical reversal in terms of experimental limitations. As more microarrays and other genomic tools become available—and hopefully increasingly affordable—the genotyping part of the problem, which traditionally has been most time-consuming, is not that complicated anymore. The real bottleneck is now phenotyping.

In an Editorial in Nature Methods June issue, we argue that this realization should be a call to arms for engineers.