During the development of multicellular organisms, and in aberrant developmental processes such as cancer, cells undergo a series of stresses, gene expression changes, and other transient events, some of which determine their ultimate fates. The historical events preceding most cell fates are unknown. Even less is known about which historical events cause a cell fate and which merely accompany it. DNA recorders are synthetic biology tools that enable cells to make a durable DNA record of ephemeral events in their history, in principle enabling biologists to correlate any type of cellular event to long term changes in the cell’s phenotype. Moreover, by recording the relative timings of the events and the fate changes, DNA recorders should make it possible to form better hypotheses about which events cause which fate changes. Our lab's goal is to realize this promise by engineering better DNA recorders. One application of particular interest to us is long-term genotoxic stress and its consequences for cell fate. As the lab grows and our technology matures, our tools for recording cell history will also be adapted to perturb cell fate in response to specific histories.