With New Research, the Genetic Code Looks More and More Like a Deliberate Choice

Researchers from Howard Hughes Medical Institute and Scripps Institute have announced their design of "DNA containing a third base pair [that] establishes a functional six-letter genetic alphabet." As reported in PNAS, they engineered a new base pair that can reside within a string of DNA code containing the natural pairs G-C and A-T. The new pair is called 5SICs-NaM but, unlike natural base pairs, it does not use hydrogen bonds to hold together. Instead, it "relies on harnessing hydrophobic...