Viral Structure (IMAGE) University of California - San Diego Caption A donut-shaped twist, or toroid, of DNA (shown in red) wedges the viral genome tightly within the protein envelope of the bacteriophage. Credit Credit: Jinghua Tang/UCSD Usage Restrictions Usage restrictions: for use in news reports of this research only (or similar language) License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.