The origin of life is one of the big unsolved scientific mysteries. Despite competing scenarios, we may have some idea of possible environments and formation of the building blocks of life. However, the process by which these self-organize into cells that evolve remains essentially unknown. Demonstrating an experimental path for the origin of evolution will provide solid scientific ground for the origin of life. Showing that such a path can be gradual will notably enhance the plausibility of origin of life events. Understanding the general principles for the origin of life also provides support for space missions, notably investments in searching for exoplanets which may harbor life.
Abiogenesis, the transition from non-living to living matter, is at the core of the origin of life question. A central hypothesis in origin of life is that of the RNA world, which proposes that RNA predates DNA and protein. Indeed, RNA molecules are capable of carrying sequence information like DNA and perform cataylsis like proteins. However, how RNA systems may self-organize to lead to biological or protobiological systems (a process called abiogenesis) remain unknown. The AbioEvo project aims to test the hypothesis that RNA-catalyzed RNA recombination, if coupled with template-based mechanisms, provides a gradual route for the emergence of evolution by natural selection. It starts from from collective autocatalysis, meaning that collections of RNA molecules can self-reproduce from their fragments. The end of our road is template-based replication, which is the copying of a RNA sequence catalyzed by a RNA. On the way, we propose that recombination allows both self-reproduction and shuffling of other sequences, and can be combined with template-based ligation. To build an evolving system, we will assemble the basic ingredients of reproduction, heredity and variation.
Concretely, we aim to show that mixtures of small RNAs can self-organize into reaction networks capable of evolution, via autocatalysis and evolution. The project decomposes this problem into five steps: (WP1) the study of molecular-level mechanisms to generate and stabilize novel sequences by recombination and templating; (WP2) collective dynamics integrating these mechanisms into the properties of reproduction with heredity, variation, and selection, in order to establish proof-of-concepts of evolutionary modes; (WP3) viability thresholds of recombination-based replicators from increasingly random substrates; (WP4) conditions for open-ended evolution toward template-based replication; (WP5) estimates of thresholds and probabilities of the proposed evolutionary processes. The project would provide first demonstrations of evolution by natural selection in a purely chemical system, gradual and experimentally accessible paths from oligomers to template-based replication, and a method to evaluate prebiotic plausibility from sequence-to-function relationships, kinetics and evolutionary dynamics.
