IntroductionA notion of life being originated from polymerization of RNA nucleotides seems to be corroborated by circumstantial evidence and some experimental results, however, how it was actually proceeded is not well understood. There are ongoing efforts to synthesize RNA nucleotides in modern labs starting from simple molecular components presumably existed on prebiotic Earth [1-4]. It appears that entire processes leading to formation of the subunits of RNA nucleotides, i.e., ribose sugar, phosphate and nucleobases (adenine (A for short), uracil (U), guanine (G) and cytosine (C)) could be naturally proceeded in prebiotic Earth environment following thermodynamic principles. Alternatively, some intermediate products might be originated from outer space and delivered to Earth. Evidence provided by meteorites suggests this possibility [5]. On the other hand, according to experiments performed in modern labs, the final process, the formation of the RNA nucleotides by joining the subunits is found to be thermodynamically difficult because the subunits must be joined together with covalent bonding that requires to overcome a high activation energy. Thus, there had to be a process that modified the activation energy and promoted the formation of the nucleotides to produce enough quantity for the subsequent polymerization.Once the concentration of RNA nucleotides had reached a certain level, the polymerization took place, and a single strand of RNA polymer was formed on prebiotic Earth. An experiment a simulated prebiotic condition shows that the polymer can grow up to 40 nucleotide units. The max length is determined by stability of the polymer that is constantly subjected to dissociation (bond breaking). The length is well short comparing the length of known short functional RNAs (70~100 units). The dissociation rate linearly increases as the polymer grows in length. In order to grow further, a mechanism that produced longer polymers had to be operated in prebiotic Earth.Autocatalytic reaction is a special property of certain molecules, by which the molecules are multiplied exponentially instead of linearly. Self-replication of RNA enzyme without help of biotic catalysts is known [6]. Also, the self-replication of synthetic molecule has been demonstrated [7]. The molecule is an amino adenosine triacid ester (AATE), which copies itself by attracting another ester molecule to its adenosine end, and an amino adenosine molecule to its ester end. These two molecules then react to form another AATE. The copying process works because of a weak bonding, known as hydrogen bonding which can be broken even by thermal vibration. Hydrogen bonding plays the same role in the self-replication of DNA.It is conceivable that self-replication with a help of non-biotic catalysts might play an essential role for the formation of RNA nucleotides and the polymerization of the nucleotides on prebiotic Earth [8]. Catalysts are widely used to increase yields in modern chemical syntheses. We speculate that non-biotic catalysts played an essential role in the formation of the nucleotides and the polymerization on prebiotic Earth. Metals and clay minerals are known to be good catalysts and certainly existed on prebiotic Earth [9, 10]. Their roles in the process were twofold. First, they provided surfaces on which the subunits were selectively adsorbed. This reaction consequently increased the concentration of the subunits on the surface and allowed the subunits to react each other more frequently. Secondly, they strained and aligned the subunits and nucleotides in proper orientations so that particular reactions became easier due to reduction of the activation energy.