An extremely interesting discovery that was published last week in Journal of the American Chemical Society, where a team discovered, characterized, and optimized an unnatural base pair for DNA. Previous attempts could only produce new nucleotide pairs that required unnatural polymerases for accurate replication. This new study is ground-breaking because the newly discovered base pairs are accurately copied by natural polymerases found in living cells. Applications for these newly discovered base pairs are being considered to improve treatment of disease, computing, and nanotechnology, among a multitude other applications who knows what
Craig Venter will do when he gets his hands on these new base pairs.

Here is the reference link and abstract for the article

Aaron M. Leconte, Gil Tae Hwang, Shigeo Matsuda, Petr Capek, Yoshiyuki Hari, and Floyd E. Romesberg. Discovery, Characterization, and Optimization of an Unnatural Base Pair for Expansion of the Genetic Alphabet. J. Am. Chem. Soc., ASAP Article 10.1021/ja078223d, Web Release Jan 25, 2008.

Abstract:
DNA is inherently limited by its four natural nucleotides. Efforts to expand the genetic alphabet, by addition of an unnatural base pair, promise to expand the biotechnological applications available for DNA as well as to be an essential first step toward expansion of the genetic code. We have conducted two independent screens of hydrophobic unnatural nucleotides to identify novel candidate base pairs that are well recognized by a natural DNA polymerase. From a pool of 3600 candidate base pairs, both screens identified the same base pair, dSICS:dMMO2, which we report here. Using a series of related analogues, we performed a detailed structure-activity relationship analysis, which allowed us to identify the essential functional groups on each nucleobase. From the results of these studies, we designed an optimized base pair, d5SICS:dMMO2, which is efficiently and selectively synthesized by Kf within the context of natural DNA.


And here is a link an article in the New Scientist describing the discovery

Artificial letters added to life's alphabet
13:07 30 January 2008
NewScientist.com news service
Robert Adler



Pretty cool stuff...