The Formation of RNA Polymers on Primitive Earth

Abstract

One of the greatest scientific mysteries of all time is the Origin of Life on Earth. Life on Earth may have emerged with a unique molecule: Ribonucleic Acids (RNA). The RNA world for the origin of life is a theory that states that life started with RNA before DNA and proteins because RNA molecules can auto-replicate and store genetic information. This thesis aims to expose how such RNA molecules could have been formed on a primitive Earth without the presence of other catalytic biomolecules such as enzymes. The model used in this thesis is the warm little ponds theory for the origin of life. RNA molecules could have been formed in these ponds thanks to wet-cold and warm-dry cycles. We used new experimental and computational technologies to try to answer this dilemma. Using a new machine, the Planet Simulator, which can mimic primitive environments by controlling five physical parameters, we found that extreme heat and low pH would destroy the building blocks of RNA. However, Molecular Dynamics computer simulations showed us that neutral pH could have led to the formation of RNA. Still, the presence of any surfaces and substrates would have decreased the polymerization rate due to the number of interactions between the RNA building blocks and the minerals substrates. We then found a new vision of where life could have come from: in super-saturated water droplets, which could have been formed by geysers or springs on primitive Earth. We tested this theory experimentally using an acoustic levitator to levitate super-saturated droplets and study them in the laboratory. Our preliminary results showed that RNA could have been formed in such droplets on primitive Earth.