Biomolecular memory mechanisms for processing many past environmental values without clocks

Determine how a biomolecular system lacking circadian and circannual clocks could record, act upon, and process approximately 25 past values of an environmental optimal-state signal in order to achieve accurate adaptation via actionable-target dynamics.

Background

The paper shows that perfect tracking of a changing environment can be achieved by adapting toward an actionable target combining the current optimal state and its rate of change. When environmental information is delayed or noisy, forecasting aids adaptation. Biological clocks (circadian and circannual) help provide reliable estimates of the present without relying on precise sensing.

Empirically, the authors find that in the absence of clocks, reaching near-optimal tracking accuracy requires the system to act on roughly 25 past values of the optimal state. They explicitly note that it is unclear how a biomolecular system could store and process such a large amount of temporal information, highlighting a concrete mechanistic gap between the theoretical requirement and known molecular capabilities.