Biology’s rules may be full of exceptions, but a new discovery has uncovered a violation in a rule so fundamental that geneticists call it the central dogma.
The molecular equivalent of writing one RNA letter in a different font can change the way a cell’s protein-building machinery interprets the genetic code, Yitao Yu and John Karijolich of the University of Rochester in New York report in the June 16 Nature. They found that occasional conversions of a genetic letter found in RNA into a slightly different form can cause a cell’s protein-building machinery to roll right through a stop sign.
That might seem like a run-of-the-mill molecular traffic violation, but it results in an entirely different protein than the one encoded by DNA — a clear violation of the central dogma.
The central dogma holds that DNA is the repository for all genetic instructions in a cell. The tenet declares that those instructions are carefully transcribed into multiple messenger RNA, or mRNA, copies, which are then read in three-letter chunks called codons by cellular machinery called ribosomes. Ribosomes then convert the mRNA instructions into proteins.