Early genetic code very resistant to mutation

Researchers of Centrum Wiskunde & Informatica (CWI) in Amsterdam show that the genetic code is remarkably resistant to DNA replication errors. This might explain the success of the common ancestor of all life, who 3,5 billion years ago developed the genetic code that resides in every organism.

Publication date: 19-03-2012

Researchers of Centrum Wiskunde & Informatica (CWI) in Amsterdam show that the genetic code is remarkably resistant to DNA replication errors. This might explain the success of the common ancestor of all life, who 3,5 billion years ago developed the genetic code that resides in every organism.

The genetic code is the language in which DNA gives instructions for protein building. All organisms use the same code from DNA to amino acids, the building blocks of proteins. One of the biggest questions for evolutionary biologists is how this genetic code evolved. Is it by chance that this code survived, or is there more to it?

Special code

With powerful computer analyses, a team of CWI researchers has shown that the current genetic code, out of all possible genetic codes, is one of the most resistant to mutations. A small replication or reading error in one of the letters in the code often results in the same or a similar amino acid. Informed guesses in earlier research already suggested that the chance that a random assignment of codes to amino acids would have this property, is very low. Harry Buhrman, Peter van der Gulik, Steven Kelk, Wouter Koolen and Leen Stougie show in Transactions of Computational Biology and Bioinformatics that, even under astronomic amounts of computer generated codes, almost no better codes can be found. They also show what the best code would look like.

Ancestor

The resistance to mutations can give insight in the early evolution of the genetic code. CWI researcher Peter van der Gulik and Wouter Hoff of the Oklahoma State University further develop this idea. In a follow-up article in the Journal of Molecular Evolution, they systematically eliminate the double codes that are responsible for the resistance to mutations. This brings them to a small set of 23 codes that codes for all amino acids. This set is a possible ancestor of the current genetic code.

Research in molecular evolution, such as the evolution of the genetic code, investigates the origin of early life. The first cells arose 3,5 to 4 billion years ago from the self-organization of molecules. Life as we know it evolved from these first cells. Advanced computer techniques from bioinformatics play an increasingly large role in molecular evolution research.

 

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