Alladi Ramakrishnan Hall

Origin of life: Perspectives from the RNA world and beyond

Supratim Sengupta

Department of Physical Sciences, IISER Kolkata

Nearly 4 billion years ago, a series of remarkable incidents led to bunch of chemicals coming together to produce a self-sustaining chemical system that eventually became capable of undergoing Darwinian evolution. What were the possible evolutionary pathways that may have eventually culminated in the emergence of the first living organism and what did evolution look like before the emergence of LUCA, the Last Universal Common Ancestor of all known living organisms? The RNA world hypothesis suggests that the first living organisms were made up of RNA molecules and preceded the DNA-protein-based life that eventually emerged and proliferated. The hypothesis confers a central role to RNA molecules in both information encoding through RNA sequences and catalysis using RNA enzymes called ribozymes. Even though circumstantial evidence can be found for the existence of an RNA world, many questions remain to be answered before we can understand how life emerged in an RNA world and the transition from an RNA world to a DNA-protein world. In this talk, I will highlight the key issues pertaining to the origin of life. By using mathematical and computational models that are guided by experiments, I will explore some of the plausible evolutionary pathways that may have led to the emergence of RNA-based “life” and the subsequent transition from the RNA world to the world where heritable genetic information is encoded in DNA sequences.