Fig. 4.

The somatic mutation catastrophe theory of aging. Somatic mutations lead primarily to a dysregulation of gene expression, but also to alterations in protein sequences, reflected in the relative weights of the arrows. Both of these consequences of somatic mutations contribute to aging, while also leading to further somatic mutations. This feedback loop could explain the age-related exponential increase in both somatic mutations and mortality with a mechanism more robust than Orgel’s.