Gene evolution has long been thought to be driven primarily by duplication or transposition mechanisms, followed by divergence of the duplicated copy. However, every evolutionary lineage harbours also so-called orphan genes, which have no homologues in other evolutionary lineages i.e. which do not appear to have arisen via gene duplication mechanisms, or have diverged to a point where their origins can not be traced anymore. Orphan genes are generally thought to be important drivers of taxon specific adaptations and interactions with the environment. New insights from comparative genomics and phylogenetic analysis suggests now that orphan genes could indeed be created through de novo evolution and it is becoming increasingly clear that this mechanism might occur at high rates, which would provide a continuous source of material for new gene functions. However, only initial evidence is available for this so far and little is known about the evolutionary dynamics and mechanisms of de novo gene emergence. The present proposal will use experimental and functional approaches to study the role and the evolutionary potential of the emergence of completely new genes from random sequences. This will open up new perspectives in understanding the evolution of genomes and the molecular mechanisms of adaptation.