Ryo Mizuuchi

In prebiotic evolution, self-replicating molecules are believed to have evolved into complex living systems by expanding their information and functions open-endedly. Theoretically, such evolutionary complexification could occur through successive appearance of novel replicators that interact with one another to form replication networks. Here we perform long-term evolution experiments of RNA that replicates using a self-encoded RNA replicase. The RNA diversifies into multiple coexisting host an

Abstract In prebiotic evolution, self-replicating molecules are believed to have evolved into complex living systems by expanding their information and functions open-endedly. Theoretically, such evolutionary complexification could occur through successive appearance of novel replicators that interact with one another to form replication networks. Here we performed long-term evolution experiments using an RNA that replicates by a self-encoded RNA replicase. The RNA diversified into multiple coex

Sustainable replication and evolution of genetic molecules such as RNA are likely requisites for the emergence of life; however, these processes are easily affected by the appearance of parasitic molecules that replicate by relying on the function of other molecules, while not contributing to their replication. A possible mechanism to repress parasite amplification is compartmentalization that segregates parasitic molecules and limits their access to functional genetic molecules. Although extent

We report empirically and theoretically that multiple prebiotic minerals can selectively accumulate longer RNAs, with selectivity enhanced at higher temperatures. We further demonstrate that surfaces can be combined with a catalytic RNA to form longer RNA polymers, supporting the potential of minerals to develop genetic information on the early Earth.

We report RNA self-replication through the translation of its encoded protein within membrane-free compartments generated by liquid-liquid phase separation. The aqueous droplets support RNA self-replication by concentrating a genomic RNA and translation proteins, facilitating the uptake of small substrates, and preventing the replication of parasitic RNAs through compartmentalization.

The reconstitution of an artificial system that has the same evolutionary ability as a living thing is a major challenge in the in vitro synthetic biology. In this study, we tested the adaptive evolutionary ability of an artificial RNA genome replication system, termed the translation-coupled RNA replication (TcRR) system. In a previous work, we performed a study of the long-term evolution of the genome with an excess amount of ribosome. In this study, we continued the evolution experiment in a

The origins of life require the emergence of informational polymers capable of reproduction. In the RNA world on the primordial Earth, reproducible RNA molecules would have arisen from a mixture of compositionally biased, poorly available, short RNA sequences in prebiotic environments. However, it remains unclear what level of sequence diversity within a small subset of population is required to initiate RNA reproduction by prebiotic mechanisms. Here, using a simulation for template-directed rec

A small (~10 cm) male pufferfish (Torquigener albomaculosus) builds a large (~2 m) sandy nest structure, resembling a mysterious crop circle, to attract females. The circle consists of radially arranged deep ditches in the outer ring region, and maze-like shallow ditches in the central region. The configuration is geometrical. Here, we examined the process of the outer ring construction, and extracted the 'rules' followed by the pufferfish. During construction, the pufferfish repeatedly excavate

The emergence of RNA self-reproduction from prebiotic components would have been crucial in developing a genetic system during the origins of life. However, all known self-reproducing RNA molecules are complex ribozymes, and how they could have arisen from abiotic materials remains unclear. Therefore, it has been proposed that the first self-reproducing RNA may have been short oligomers that assemble their components as templates. Here, we sought such minimal RNA self-reproduction in prebiotical

Adaptation to various environments is a remarkable characteristic of life. Is this limited to extant complex living organisms, or is it also possible for a simpler self-replication system to adapt? In this study, we addressed this question by using a translation-coupled RNA replication system that comprised a reconstituted translation system and an RNA "genome" that encoded a replicase gene. We performed RNA replication reactions under four conditions, under which different components of transla

Single-stranded RNAs (ssRNAs) are utilized as genomes in some viruses and also in experimental models of ancient life-forms, owing to their simplicity. One of the largest problems for ssRNA replication is the formation of double-stranded RNA (dsRNA), a dead-end product for ssRNA replication. A possible strategy to avoid dsRNA formation is to create strong intramolecular secondary structures of ssRNA. To design ssRNAs that efficiently replicate by Qβ replicase with minimum dsRNA formation, we pre

The integration of individually replicating genes into a primitive chromosome is a key evolutionary transition in the development of life, allowing the simultaneous inheritance of genes. However, how this transition occurred is unclear because the extended size of primitive chromosomes replicate slower than unlinked genes. Theoretical studies have suggested that a primitive chromosome can evolve in the presence of cell-like compartments, as the physical linkage prevents the stochastic loss of es

Abstract The integration of individually replicating genes into a primitive chromosome is a key evolutionary transition in the development of life, allowing the simultaneous inheritance of genes. However, how this transition occurred is unclear because of the extended size of primitive chromosomes, which replicate slower than unlinked genes. Theoretical studies have suggested that a primitive chromosome can evolve in the presence of cell-like compartments, as the physical linkage prevents the st