Disclosed herein are methods and platforms using Receptor Compartmentalized Partnered Replication (CPR), in which the partner gene is a receptor, signal transduction pathway, or metabolic pathway that leads to the production of an effector molecule for the receptor or signal transduction pathway. The signal transduction pathway or receptor is coupled to the production of a thermostable polymerase. Emulsification of libraries of organisms with primers that can amplify the partner gene led to the selective amplification of those partner genes that were best able to produce the thermostable polymerase during thermal cycling of the emulsion.