| Biomolecule fossilization products reveal the history of life on Earth and beyond
| Proteins, lipids, and sugars are the fundamental structural building blocks of life. The tissues they generate contain molecular heterogeneities that inform about interrelationships (=phylogeny), biomineralization, tissue identity, and metabolic performance. Although such biological signatures have the potential to provide invaluable evidence of the evolutionary history of life and its building blocks, most molecular information is thought to be lost in deep time. Here I challenge the paradigm of the deep-time degradation of biomolecular signatures based on the first analyses of patterns in the molecular composition of carbonaceous fossils sampled across the tree of life, their associated sediments, and modern tissue equivalents. Statistical analyses of the molecular and mineralogical composition of fossils, and experimental modelling of observed reaction schemes, reveal that biomolecules transform during fossilization through oxidative crosslinking into N-, O-, S-heterocyclic polymers. Such endogenous fossil organic matter preserves heterogeneities reflecting phylogenetic and physiological signatures in living organisms. I will illustrate how diagenetic alterations of complex organic matter on Earth and in Space impact the preservation of biosignatures. Based on these insights, I will showcase how molecular signatures can be used to elucidate evolutionary responses to major environmental and ecological perturbations in the past, and to predict future biotic reactions to a changing climate. The broad range of potential applications places molecular biosignatures at the forefront of tools to access fundamental data on the interplay between the geosphere and biosphere previously hidden in the geological record. |
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