Genetic Code Has Its Limits

As long as there are variations to threaten our species’ ability to adapt, nature will evolve. To understand this cycle of evolution you have to first understand the origin of genetic code and how it expanded. A team of biologists has published a new study which explains that the genetic code is in fact limited in its developmental capacity.

All of the organisms in existence translate the genetic sequences of DNA and RNA (nucleic acids) into amino acid sequences. The proteins that carry out cell functions are made up of these amino acids. This process follows a universal set of rules – and researchers believe these rules are the so-called brick wall in the way of expanding the genetic code.

The research was completed by a team of scientists from the Institute for Research in Biomedicine, working with researchers from the Centre for Genomic Regulation. The team has been able to demonstrate that 3,000 million years ago genetic code evolved to include no more than 20 amino acids, and that’s all there’s ever going to be (in nature anyway). Expansion is impossible due to the functional limitations of the transfer RNAs, the molecules that serve as interpreters between genes and proteins.

The study goes on to explain that the translation mechanism within RNAs is limited in the number of amino acids it can recognize because a larger number increases the probability of an error in the translation, leading the proteins to continually mutate. In other words, if the information being transferred from the gene to the protein is somehow lost in translation it could have catastrophic consequences. Nature significantly decreased the chances of this happening by decreasing the messengers.

As lead researcher Lluís Ribas de Pouplana explained in the publication Science Advances, an organism’s ability to adapt lies squarely on the shoulders of protein synthesis, so it’s critical to biological systems that the information is transferred correctly.

Increasing genetic code by building proteins with customized amino acids is one of the goals scientists working with synthetic biology are pursuing. Doing this would allow scientists to assign specific functions to a specific amino acid. Researchers use organisms like bacteria and work in highly controlled systems to produce proteins with specific characteristics that will also allow them to be identified as synthetic, a key function of effective biotechnological systems.

Synthetic biology combines various disciplines from within engineering and biology, such as biotechnology, molecular biology, evolutionary biology, biophysics, systems biology, genetic engineering and computer engineering, and describing the field depends a lot on your approach; as an engineer or as a biologist. It was originally considered a field of biology however, chemical and electrical engineering have started to play a larger role in recent years.

In addition to the numerous technical and scientific challenges synthetic biology faces, there are the ethical and biosecurity questions. Because of previous issues raised with genetically modified organisms (GMOs) however, there are already extensive regulations in place in the U.S. and Europe.

Image courtesy of Wikimedia Commons user: Artur Warchavchik

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