The Double Code Hypothesis of Ageing

Ageing remains one of biology’s most fundamental unresolved questions. Existing explanations often attribute ageing to stochastic damage accumulation, adaptive programmes, or interacting hallmarks, yet none fully explains why ageing emerges so broadly in organisms that undergo development. Here, I introduce the Double Code Hypothesis of Ageing, which frames ageing as an inevitable consequence of life’s dual inheritance system: the genome and the epigenome. In this manuscript, “code” is used in a computer-science-like sense, closer to source code than to the specialised meaning used in code biology: an organised set of biological instructions whose effects depend on being read, interpreted, maintained, and executed by cellular machinery.I propose that ageing is not merely the progressive accumulation of epigenetic noise within an individual, but the consequence of an inherent instability in a dual inheritance system whose two informational layers must remain functionally aligned across cellular and organismal generations. The relative stability of the genome allows long-term information preservation, whereas the plasticity of the epigenome enables development, differentiation, and adaptation, but also makes this layer vulnerable to cumulative misalignment.This progressive loss of genome–epigenome coordination acts as a natural, non-programmed limit on lifespan in complex organisms. Rather than an encoded death programme, ageing is described as increasing informational disorder emerging from the unresolved tension between genetic stability and epigenetic plasticity. This falsifiable framework offers experimental predictions in model systems such as Schizosaccharomyces pombe and provides a mechanistic explanation for why ageing exists.