The Precambrian era is associated with the origin of life on primitive Earth. It was, in fact, in that era that ribonucleic acid (RNA) was first acquired. From this evolved the genomic deoxyribonucleic acid (DNA) that later generated the biomolecules that formed the first cell. In this way, with the ongoing changes in environmental factors, the first cells evolved to give rise to higher multicellular organisms, i.e., plants and animals. Radiolarians and diatoms are organisms that have been conserved since the Precambrian era. However, although these organisms are alive (they can be considered as living fossils), they do not suffice to explain the origin of life. To understand the origin of life, the interactions among inorganic compounds that existed in the Precambrian era must be elucidated. In this context, calcium, barium, or strontium silico-carbonates (usually called silica-biomorphs) have been simply named biomorphs that emulate the morphologies of organisms, such as flowers, leaves, stems, helices, worms, radiolarians, and diatoms, among others. The shapes of the biomorphs can be implicated in the origin of life due to their similarity with the shapes of the cherts of the Precambrian era. However, biomorphs are inorganic compounds that do not contain any organic biomolecules such as nucleic acids or proteins inside their chemical structures. The aim of the present work was to synthesize calcium, barium, or strontium silica biomorphs in the presence of nucleic acids: genomic DNA (linear double helices), plasmid DNA (circular helices), and RNA (a single chain helix). The morphology of these biomorphs was assessed through scanning electron microscopy (SEM). The obtained microphotographs revealed that nucleic acids direct the synthesis of biomorphs toward a unique and specific structure for each of these biomolecules. The chemical composition and the crystalline structure were determined through micro-Raman spectroscopy and X-ray diffraction to characterize the most characteristic crystalline phases. The biomorphs obtained from calcium, barium, or strontium corresponded to crystalline structures of CaCO 3 (calcite, aragonite, vaterite), BaCO 3 (witherite), or SrCO 3 (strontianite), respectively. These silica-carbonates (considered as reminiscence of the shape found in the cherts of the Precambrian) can be a linking point between the Precambrian era and the subsequent eras. To the best of our knowledge, this is the first report in which the interaction of nucleic acids in the synthesis of biomorphs has been evaluated.

The origin of life on Earth is associated with the Precambrian era, in which the existence of a large diversity of microbial fossils has been demonstrated. Notwithstanding, despite existing evidence of the emergence of life many unsolved questions remain. The first question could be as follows: Which was the inorganic structure that allowed isolation and conservation of the first biomolecules in the existing reduced conditions of the primigenial era? Minerals have been postulated as the ones in charge of protecting theses biomolecules against the external environment. There are calcium, barium, or strontium silica–carbonates, called biomorphs, which we propose as being one of the first inorganic structures in which biomolecules were protected from the external medium. Biomorphs are structures with different biological morphologies that are not formed by cells, but by nanocrystals; some of their morphologies resemble the microfossils found in Precambrian cherts. Even though biomorphs are unknown structures in the geological registry, their similarity with some biological forms, including some Apex fossils, could suggest them as the first “inorganic scaffold” where the first biomolecules became concentrated, conserved, aligned, and duplicated to give rise to the pioneering cell. However, it has not been documented whether biomorphs could have been the primary structures that conserved biomolecules in the Precambrian era. To attain a better understanding on whether biomorphs could have been the inorganic scaffold that existed in the primigenial Earth, the aim of this contribution is to synthesize calcium, barium, and strontium biomorphs in the presence of genomic DNA from organisms of the five kingdoms in conditions emulating the atmosphere of the Precambrian era and that CO2 concentration in conditions emulating current atmospheric conditions. Our results showed, for the first time, the formation of the kerogen signal, which is a marker of biogenicity in fossils, in the biomorphs grown in the presence of DNA. We also found the DNA to be internalized into the structure of biomorphs.

The Earth has undergone at least four great glaciations, during which the ice layers and the glaciers have expanded all over the planet, corresponding to significant drops in global temperatures that lasted millions of years. Since the Precambrian era, ice ages have occurred at intervals of several millions of years. It is considered that the impact on the biosphere was large, because life was on the brink of disappearing completely from the planet. During these glaciation periods, carbon was reassigned, with the subsequent formation of carbonates called cap carbonates, which present stromatolite-like activity. These findings prove that life was conserved even during the glacial period. Knowledge on life conservation during the glacial period through stromatolites that have endured until the present day, is of special relevance. In recent investigations, in vitro structures have been synthesized; these crystalline aggregates have been named biomorphs because they mirror the morphologies of primitive organisms called Precambrian cherts. These biomorphs have been synthesized at different temperatures (from room temperature to lower ones). The aim of the present work was to synthesize CaCO 3 , BaCO 3 , and SrCO 3 silica−carbonate biomorphs at three low temperatures (4 °C, −20 °C, and −70 °C). CaCO 3 biomorphs present almost the same morphology at all temperatures with a calcite crystalline structure, whereas BaCO 3 and SrCO 3 biomorphs present remarkably different morphologies depending on temperature with witherite and strontianite crystalline structure, respectively.

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An analytical hybrid platform combining DCDR and GERS effects is presented. An absolute mass detection of 1 fg of IL-6 was reached.