Walter Fontana (Harvard Medical School; SFI External Professor)
Abstract. The process of aging is difficult to pin down conceptually, let alone to measure longitudinally in individuals. It is far less difficult to agree on its endpoint: death. Since death is a singular event for an individual, a focus on death forces a population-centric approach. Whether anything can be said about the process of aging in individuals by measuring the death-time (i.e. process endpoint) distribution in populations depends on whether changes that occur in this distribution in response to perturbations exhibit sufficient regularities. We found that the lifespan distribution of the nematode Caenorhabditis elegans (aka “the worm") responds to numerous–but not all–physical, chemical, and genetic interventions by rescaling time. This is as simple as it is mind-boggling. (Or perhaps it is either simple or it is mind-boggling.) The observation implies that across many interventions differing in modality, intensity, and targets the risk of any cause of death must rescale equally. This in turn suggests the existence of an organism-wide state variable that determines mortality. At present, we have no molecular explanation of this phenomenon.
With Nicholas Stroustrup, Winston Anthony, Zachary Nash, Vivek Gowda, Adam Gomez, Isaac Lopez-Moyado, and Javier Apfeld.
Nature 320 (2016): 103-107.