Designer DNA Base

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Designer DNA Base described in a report in news@nature, 16 Mar 2005. Floyd Romesberg and colleagues at the Scripps Research Institute, California, have designed an artificial or “Fake Base” that can be incorporated into DNA. Bases are chemical code letters that form the genetic information in DNA. DNA has four of these: Adenine, Thymine, Cytosine and Guanine, or A, T, C, and G. The ATCG bases link together to form pairs along the double helix of the DNA molecule. A's always pair with T's and C's with G's. To make a copy of the DNA's genetic information, base pairs are split and the two strands of the DNA molecule are then pulled apart. A large protein called an enzyme, then runs along each strand and adds new matching pairs to the bases of each separated strand.

Romesburg's team have designed a “Fake Base” molecule, named 3FB, that fits onto the DNA helix and can be picked up by the copying enzyme and incorporated into a new DNA molecule. Unlike the natural bases, 3FB pairs only with itself, rather than with a complementary base, and the natural copying enzyme does not match artificial 3FB's as efficiently as it does with the natural ATCG bases. It averages about one copy mistake for every 1,000 duplications, which is about 100 times the base mismatch rate in real life. Romesberg claims he was happy with that and is not trying to “evolve polymerases that recognise fake base pairs and work with them more efficiently.” The news@nature article claims “artificial sequences could one day answer questions about evolution.”

Editorial Comment: It pays to note that the 3FB molecules did not get into DNA by naturalistic or chance or random process. 3FB molecules got onto the DNA, and could be matched up by the copying enzyme, only because intelligent scientists made use of their knowledge of how DNA already worked, and therefore deliberately designed a molecule to fit the pre-existent working system. Unless your prejudice is overwhelming, this is good evidence the original system, with its more efficient base pairs and copying enzyme, also did not arise by naturalistic, chance or random processes and was created by a much more efficient base pair scientist. The only answer to questions about evolution this study will provide is that it proves DNA did not evolve. It shows very clearly that it takes intelligent creative design to make a system for storing and using genetic information. (Ref. biotechnology, design, intelligence)