March 06, 2013

“Evolution Is Not Over” –New Insights Into the Genetic Code

Swiss Researchers are looking several billion years back in time, when life on Earth was just beginning to examine how a primitive protein was able to evolve. The journey into the past also afforded the scientists a glimpse into the future of synthetic biology. The first primitive life forms that developed on Earth around four billion years ago had little in common with today’s organisms. They probably managed without proteins. And the first proteins that formed in the following few hundred million years to become essential elements of the living world also differed from those of today: scientists assume that the first proteins were composed of a reduced repertoire of only seven or eight different amino acids.

Apart from the twenty universal amino acids, a more complex incorporation mechanism allows the use of a twenty-first amino acid called selenocysteine. It is found in many living organisms, including humans. In certain microorganisms, the archaea, there is even a twenty-second amino acid: pyrrolysine. This leads scientists to conclude that the genetic code has continued to evolve over the last billion years.

“Evolution obviously isn’t over. It could well be that additional amino acids will be incorporated into the code in due course,” says Donald Hilvert, a professor at the Laboratory of Organic Chemistry at ETH-Zurich.

The repertoire of today’s proteins, however, typically contains twenty amino acids. A team of researchers headed by Hilvert, a professor has simulated how the minimal starting amino acid repertoire might have expanded in the course of evolution. Not only do the researchers draw conclusions regarding the past from their work, they also gain important insights into future directions for synthetic biology.

Read more: "Evolution Is Not Over" –New Insights Into the Genetic Code — The Daily Galaxy.

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