'Near Optimal' Genetic Code Discovered

Researchers worked to create a model that may help explain the complexities involving the origins of life via RNA signaling that develops into a modern "genetic code."

"Our model shows that today's genetic code probably resulted from a combination of selective forces and random chance," Justin Jee said via a press release, a doctoral student at NYU School of Medicine and the paper's lead author.

The study authors looked at the genetic composition of the code, which allowed proteins to be built from amino acids with high specificity that's based on the information stored in a RNA or DNA genome. According to this translation process between the nucleic acids and amino acids, they found a remarkable and mysterious universe that's similar to a code shared in all organisms from bacteria to human beings.

Yet the genetic code is also not completely optimal in terms of specifying particular amino acids for particular nucleic acid sequences.

The study notes the history of the code's discovery, via a press release: "Since the code's discovery in the 1960's, researchers have wondered: how is it that a near-optimal code became so universal?

"To address this question, the researchers created a model of genetic code evolution in which multiple "translating" RNAs and "genomic" RNAs competed for survival. Specifically, the translating RNAs were able to link amino acids together based on information stored in genomic RNA, but with varying levels of specificity.

"In running computer simulations of RNA interactions, they could see two phenomena. First, it was necessary for the translating and genomic RNAs to organize into cells, which aided the coordination of a code between the translating and genomic RNAs. Second, selective forces led a single set of translating RNAs to dominate the population. In other words, the emergence of a single, universal, near-optimal code was a natural outcome of the model. Even more remarkably, the results occurred under realistic conditions-specifically, they held under parameters such as protein lengths and rates of mutation that likely existed in a natural RNA world."

"The most elegant ideas in this paper are rather obvious consequences of a well-studied model based on sender-receiver games," said Mishra, the paper's senior author, via the release. "Yet the results are still very surprising because they suggest, for example, that proteins, the most prized molecules of biology, might have had their origin as undesirable toxic trash. Other studies based on phylogenomic analysis seem to be coming to similar conclusions independently."

More information regarding the study can be found via the Journal of Royal Society Interface.