Genetic code biased

The hyperthermophiles employ the universal genetic code but some biases are detectable, including preferential use of only two of the six arginine codons and rare usage of cysteine codons. 

E.7.2.2 The Most Fundamental Step of Evolution-Natural Selection Is to Access a New Energy Source at No Additional Cost in Energy by the Biased Genetic Code... 

The field of DNA vaccines centers on the ability to deliver genetic material, coding, for desired protein antigens in the context of a mammalian expression vector (Donnelly et al., 1997). It was realized that the immunostimulatory properties observed with DNA vaccines, namely the ability to induce a Thl biased or cell mediated immune response, was attributable in part to the presence of CpG motifs within the plasmid DNA (Klinman et al., 1997). In fact, it was demonstrated that the quality of immune activation by DNA vaccines could be influenced by the deliber-ate alteration of CpG content (Krieg et al., 1998). Further, with the identification of neutralizing CpG motifs it became possible to remove any neutralizing influence from the DNA vaccine plasmids. The end result was the optimization of DNA vaccine plasmids, with respect to immune activation (Krieg et al., 1998). 

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