It is easier to copy something than to develop something new - a principle that was long believed to also apply to the evolution of genes. According to this, evolution copies existing genes and then adapts the copies to new tasks. However, scientists from the Max Planck Institute for Evolutionary Biology in Plön have now revealed that new genes often form from scratch. Their analyses of genes from mice, humans and fish have shown that new genes are shorter than old ones and simpler in structure.