the Lewis Carroll classic, Through the Looking Glass, Humpty Dumpty states, “When I use a word, it means just what I choose it to mean — neither more nor less.” In turn, Alice (of Wonderland fame) says, “The question is, whether you can make words mean so many different things.” All organisms on Earth use a genetic code, which is the language in which the building plans for proteins are specified in their DNA. It has long been assumed that there is only one such “canonical” code, so each word means the same thing to every organism. While a few examples of organisms deviating from this canonical code had been serendipitously discovered before, these were widely thought of as very rare evolutionary oddities, absent from most places on Earth and representing a tiny fraction of species. Now, this paradigm has been challenged by the discovery of large numbers of exceptions from the canonical genetic code, published by a team of researchers from the U.S. Department of Energy Joint Genome Institute (DOE JGI) in the May 23, 2014 edition of the journal Science.
It has been 60 years since the discovery of the structure of DNA and the emergence of the central dogma of molecular biology, wherein DNA serves as a template for RNA and these nucleotides form triplets of letters called codons. There are 64 codons, and all but three of these triplets encode actual amino acids — the building blocks of protein. The remaining three are “stop codons,” that bring the molecular machinery to a halt, terminating the translation of RNA into protein. Each has a given name: Amber, Opal and Ochre. When an organism’s machinery reads the instructions in the DNA, builds a protein composed of amino acids, and reaches Amber, Opal or Ochre, this triplet would signal that they have arrived at the end of a protein.
“This is sort of a ‘stop sign,'” Rubin said. “But what we saw in the study was that in certain organisms, the stop sign was not interpreted as stop, rather it signaled to continue adding amino acids and expand the protein.”
Why does this remind some of us of human languages?
In some bilingual places, if you are offered something at dinner, Thanks! means yes, but the same word in French, merci, means no.
And if it turns out to be like human languages, well, …
See also: New theory of physics attempts to incorporate information’s “central role” in nature
Genome map shows comb jellies had separate course of evolution