> So... like... what happened, exactly? A group added a new DNA base pair ("X" and "Y") to a strain of E. coli. In genes, codons are triplets of DNA letters t

> So... like... what happened, exactly? A group added a new DNA base pair ("X" and "Y") to a strain of E. coli. In genes, codons are triplets of DNA letters that transcription and translation machinery converts into specific amino acids. The mechanisms by which this happens are complex, but well understood. The new DNA letters were used to make new codons that could be translated to particular, novel, amino acids.