The following is quickly becoming my favorite quote within the evo/creo debate. The author of the quote (Ernst Mayr) was involved in evolution during the time the theory was "finalized" in the form of the Evolutionary Synthesis (now called the Modern Synthesis). He was around well before the discovery of DNA. The following quote deals with how the discovery of DNA and its manipulation has affected how we look at the theory.
"By the end of the 1940s the work of the evolutionists was considered to be largely completed, as indicated by the robustness of the Evolutionary Synthesis. But in the ensuing decades, all sorts of things happened that might have had a major impact on the Darwinian paradigm. First came Avery's demonstration that nucleic acids and not proteins are the genetic material. Then in 1953, the discovery of the double helix by Watson and Crick increased the analytical capacity of the geneticists by at least an order of magnitude. Unexpectedly, however, none of these molecular findings necessitated a revision of the Darwinian paradigm--nor did the even more drastic genomic revolution that has permitted the analysis of genes down to the last base pair." --Ernst Mayr