For decades, scientists working with genetic material have labored with a few basic rules in mind. To start, DNA is transcribed into messenger RNA (mRNA), and mRNA is translated into proteins, which are essential for almost all biological functions. The central principle regarding that translation has long held that only a small number of three-letter sequences in mRNA, known as start codons, could trigger the production of proteins. But researchers might need to revisit and possibly rewrite this rule, after recent measurements from a team including scientists from the National Institute of Standards and Technology (NIST).