Snaking Through the Ladder (IMAGE) University of Texas at Austin Caption This shows a model of the "threading tetra-intercalator" bound up in the double helix of a DNA sequence. Credit Brent Iverson Usage Restrictions None 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.