Orateur
Summary
In this talk I will present an idealised model of an RNA-world "protocell", and some of the evolutionary phenomena this gives rise to. In this model a protocell is simply a vesicle-like container carrying a well stirred mixture of "polymers" which can function as abstract analogues of certain (hypothetical) kinds of ribozymes - i.e., they function both as informational templates to be replicated, and as replicase enzymes to catalyse such replication. Replicases vary in the classes of templates which they can replicate (i.e., in the template motifs which they recognise and bind to). Some molecular species function as self-replicases. As the molecular population increases through replication, the vesicle grows until it reaches a critical size at which it fissions. The result is a system in which there are two distinct but coupled selectional processes: one at the molecular level, one at the cellular level. This is a (highly simplified!) model in which it might be possible to investigate some aspects of the evolution of cell signalling. In any case, I will illustrate some of the (perhaps unexpected?) consequences of this architecture.