Selectively Advantageous Instability and Information Theory in Sex-specific Aging

Biological information is generally thought to be subject to selection for faithful maintenance. However, accurate preservation is often combined with regulated mechanisms that generate state change. Selectively advantageous instability (SAI) of biological information is modeled here as instability that is favored because useful alternatives become accessible. Modeling shows that active destabilization is favored above a threshold determined by environmental change, passive error, destabilization cost, and the relative adaptive targeting of active versus passive variation. When actively generated variation is sufficiently structured, selection simultaneously favors increased maintenance and increased active destabilization of the same information channel. This relationship is described as stabilization-destabilization complementarity. Shannon entropy quantifies uncertainty, whereas relative entropy quantifies mismatch between generated and fitness-relevant state distributions. Aging is not produced by reversible state-space exploration alone. Aging results when selected exploration also causes persistent or cumulative loss of maintained organization. Age and sex extensions show how delayed costs and shared genetic control can generate antagonistic pleiotropy and sexual conflict. A unified interpretation is provided in which SAI can be selected as a mechanism of adaptive state space exploration even when long term information displacement is costly.