A discovery by UNL researchers expands understanding of the genetic code, and may help revise a tenet of this universal language of life.

In cells, the genetic code essentially provides instructions for creating proteins, the basic structural molecules of life. The code includes a series of unique three-letter “code words,” called codons. These genetic passwords dictate insertion of amino acids, the building blocks of proteins. While codons may change to code for different amino acids in different organisms, a long-held precept of the genetic code is that one codon provides the password only for one amino acid in an organism.

Not always, UNL scientists discovered.

“We showed that one codon may code for two amino acids, even within the same gene. That’s really unexpected,” said Vadim Gladyshev, the biochemistry professor whose team made the discovery.

Members of the UNL research team that made the genetic code discovery include, from left, Alexey Lobanov, senior research associate who handled the computing analysis; Anton Turanov, former graduate student who did much of the experimental work; and Vadim Gladyshev, professor of biochemistry. Photo by Joel Brehm/Office of Research.

The team and other collaborators reported the findings in the Jan. 10 issue of the international journal Science.

Their discovery of the multi-tasking codon, called UGA, raises the question of whether codons in other organisms can do the same thing. They’re now investigating UGA’s function in mammals.