In 2001 the sequencing of the human genome revealed a surprising fact: over 45% of our genome comes from sequences called transposons, ‘jumping’ genes that can move within the genome, generating new copies of themselves through molecular mechanisms of cut-and-paste or copy-and-paste. Because of this characteristic, they are also called ‘selfish genes’, interested only in replicating, in a way similar to the action of viruses. However, new research carried out in collaboration between SISSA - Scuola Internazionale Superiore di Studi Avanzati and IIT - Istituto Italiano di Tecnologia, led by Professors Stefano Gustincich and Remo Sanges, has revealed important and unexpected functions associated with these transposons, debunking their reputation as selfish genes.