Artificial nukleotides (IMAGE) University of Cologne Caption Structural comparison of DNA and the artificial TNA, a Xeno nucleic acid with the natural base pairs AT and GC and an additional base pair (XY). Credit Stephanie Kath-Schorr Usage Restrictions only to use in combination with the press release License Original 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.