This paper investigates the evolution of two types of simple Genotype Phenotype Mappings (GPMs): a many-to-one mapping and a one-to-many mapping. Both GPMs are under genetic control. For both types of mappings different Regions Of Maximum Adaptability (ROMAs) are found. These ROMAs are the regions - in a paramterized space of GPMs - evolution leads to. The attraction towards these ROMAs increases as selection pressure increases. Finally, this paper discusses the evolution of pleiotropy and the ROMAs it leads to.
