As organisms adapt to their environment, adaptations that serve them in their current environment can become liabilities if that environment changes. The control of traits that are an asset in one situation and a liability by the same gene is called antagonistic pleiotropy. In the March 16, 2020, online issue of Nature Genetics, researchers reported a method to systematically identify mutations that conferred antagonistic pleiotropy – in the form of resistance to one drug, but heightened sensitivity to another – in acute myeloid leukemia (AML) cells.