Over the decades, synthetic biologists trying to expand life's genetic alphabet have come up with a handful of alternative genetic letters. (sciencemag.org)
Surprisingly, other than adding a transporter protein that carried the new genetic letters into the bacteria, the team did not have to modify the cells at all. (newscientist.com)
To make a protein, the sequence of genetic letters in each gene gets copied into matching strands of RNA, which then float out of the nucleus to guide the protein - making machinery of the cell. (technologyreview.com)