Sedimentary models of fossil biomolecules, principles and methodological improvements

Deamination has historically been important for authenticating ancient biomolecules. However, expanding paleogenomic datasets indicate that damage patterns are more influenced by burial hydrology and microstructural context than by molecular age or ancestry. Fossils interact with their environments differently: some form closed, water-restricted compartments that preserve minimally damaged endogenous biomolecules, whereas others serve as open molecular reservoirs in which infiltrated environmental biomolecules undergo extensive deamination from repeated water exposure. Reliance on deamination alone can therefore suppress endogenous signals and complicate the interpretation of exogenous sequences. By introducing the molecular sedimentation model for fossil biomolecules, this Perspective outlines a source tracing framework that integrates fossil microstructure, ecological reference sets, and species-specific fragments to enable more reliable molecular inference across diverse depositional environments.