Origins of new genes and evolution of their novel functions

The origination of novel genes is an important process during the evolution of organisms because it provides critical sources for evolutionary innovation. Addressing how novel genes emerged and acquired novel and adaptive functions is of fundamental importance. Here we summarize the newest advances in our understanding of the molecular mechanisms and genome-wide patterns of new gene origination and new gene functions. We pay special attention to the origins of noncoding RNA genes and de novo genes, whose processes had been previously overlooked but are gaining increasingly visible importance. We then introduce recent findings that have opened a path to the study of the evolution of novel functions and pathways via novel genes. We also discuss the important issues and potential developments in the field.