New Finding Changes Long-Held Theory About How DNA Replicates

Since James D. Watson and Francis Crick discovered the structure of DNA in 1953, the primary paradigm of genetics has been that hydrogen bonding between the two pairs of bases--adenine and thymine, cytosine and guanine--not only holds the DNA double helix together, but also provides the template for production of a new strand of DNA when a cell reproduces.

But new research by chemist Eric Kool of the University of Rochester changes the understanding of this vital biological process that is common to all life forms. He found that it is the three-dimensional shapes of the bases, not their ability to form hydrogen bonds, that leads to accurate replication. Kool reports in the Sept. 30 Proceedings of the National Academy of Sciences that he synthesized non-hydrogen-bonding artificial bases with the exact same shapes as the natural bases. The artificial bases were incorporated into newly synthesized DNA in the appropriate positions, indicating that hydrogen-bonding is unnecessary.