Newswise — Curious bits of DNA tucked inside genomes across all kingdoms of life historically have been disregarded since they don’t seem to have a role to play in the competition for survival. Or so researchers thought. These DNA pieces came to be known as “selfish genetic elements” because they exist, as far as scientists could tell, to simply reproduce and propagate themselves, without any benefit to their host organisms.
They were seen as genetic hitchhikers that have been inconsequentially passed from one generation to the next. Research conducted by scientists at the University of California San Diego has provided fresh evidence that such DNA elements might not be so selfish after all. Instead, they now appear to factor considerably into the dynamics between competing organisms.
Publishing in the journal Science , researchers in the School of Biological Sciences studied selfish genetic elements in bacteriophages (phages), viruses that are considered the most abundant organisms on Earth. To their surprise, researchers found that selfish genetic elements known as “mobile introns” provide their virus hosts with a clear advantage when competing with other viruses: phages have weaponized mobile introns to disrupt the ability of competing phage viruses to reproduce. “This is the first time a selfish genetic element has been demonstrated to confer a competitive advantage to the host organism it has invaded,” said study co-first author Erica Birkholz, a postdoct.