WIDENING THE DNA DOUBLE HELIX

Abstract

NOT CONTENT WITH REGUlar old run-of-the-mill DNA, a research team has supersized it and made it glow. Graduate students Haibo Liu andjianmin Gao, chemistry professor Eric T. Kool, and coworkers at Stanford University have created an alternative genetic system based on expanded DNA bases [ Science , 302, 868 (2003)]. The fluorescent modified bases hybridize with conventional bases to form a double helix that's wider and more stable than the one found in nature. Potential applications of the more generously endowed DNA include DNA sensing and genetic tissue typing. The new study also raises questions about whether supersize DNA-based organisms might exist on other planets. Hundreds of versions of altered DNA backbones can be found in the literature. And modified base pairs have been designed by several groups—including those of Steven A. Benner at the University of Florida, Gainesville; Floyd E. Romesberg and Peter G Schultz at Scripps Research Institute; and Shigeyuki 'Ybkoyama and Ichiro Hirao at ...