A LIQUID CRYSTAL WORLD AT THE ORIGIN OF LIFE

The conundrum of the Origin of Life has always fascinated humankind, given its intimate relation with a fundamental question such as {it ``where do we come from?"}. In order to answer this question, from centuries the scholars of the field have studied the conditions present in our Universe and on our planet at the age when Life emerged, and tested whether Life could raise in such a complex scenario. A general pathway has been defined to recapitulate the origin of Life from simple inorganic chemicals up to complex systems, and it inevitably passes through the so-called {it"RNA World"}; a stage on our Earth when Life consisted of long linear polymers of RNA both carrying genetic information and catalyzing their very own replication and supporting a primitive metabolism. Still, up to nowadays we lack a good explanation of how long biopolymers could have formed on the ancient Earth, given that RNA phosphodiester bonds are intrinsically unstable and that the most common models of non-enzymatic polymerization result in very short products. The necessity to define a complete pathway for the origin of Life has pushed us to develop a new model to drive the formation of a ribozyme, based on the self-assembly of nucleic acids molecules. Exploiting a wide set of tools belonging to the fields of molecular biology, chemistry and soft matter physics, in this work we show that the self-assembly and supramolecular ordering of nucleic acids is a phenomenon with deep roots in their very physicochemical properties, leading to the emergence of liquid crystal ordering in mixtures of nucleosides having different chemical modifications and polymerization state. The formation of long physical polymers with discontinuities or completely lacking a backbone, while still structured following Watson-Crick selectivity, raises questions on the origin of the famous double helix, which seems now to be found in the features of single nucleosides interactions. In this thesis the effect of supramolecular organization and symmetry breaking on short RNA oligomers and chemically activated nucleosides is described and characterized, showing that the chemical reactivity is altered favoring the formation of long linear polymers, and highlighting a new potential pathway for the Origin of Life.