Simplifying genetic codes to look back in time

Aug 24, 2012

(Phys.org)— Daisuke Kiga and co-workers at the Department of Computational Intelligence and Systems Science at Tokyo Institute of Technology, together with researchers across Japan, have shown that simpler versions of the universal genetic code, created by knocking out certain amino acids, can still function efficiently and accurately in protein synthesis. The researchers conducted experiments altering the genetic codein a test tube.

They removed the amino acid tryptophan and discovered that the resulting simplified code could still generate proteins as before. By knocking out individual and observing the effects, scientists will be able to understand how early primordial organisms may have functioned and evolved. There will be also numerous applications for simplified genetic strains in laboratory experiments, which could potentially prevent non-natural genetically modified materials from entering the natural world.

Daisuke Kiga and co-workers of the Department of Computational Intelligence and Systems Science at Tokyo Institute of Technology, together with researchers across Japan, have shown that simpler versions of the universal genetic code - created by knocking out certain amino acids - can still function efficiently and accurately in . The researchers conducted cell-free experiments altering the genetic code.

All current life forms on Earth have 20 amino acids in their genetic code. However, scientists believe that this was not always the case, and that organisms evolved from simpler genetic codes with fewer amino acids. Amino acids are linked in accordance with codons – a 3-letter combination of the four base nucleotides (G, A, T and C) in a genetic code. There are 64 possible codons, and so most amino acids are produced by several different codons, except for tryptophan and , which are generated by just one codon each. Tryptophan is thought to be the most recent amino acid to become part of the universal genetic code.

Kiga and his team took the codon for tryptophan, and reassigned it to code for the amino acid alanine instead. They discovered the resulting simplified code could still generate proteins as before. The researchers also reassigned another codon originally for the amino acid cysteine and replaced it with serine. This simplified code without cysteine was able to synthesise an active enzyme.

By knocking out individual amino acids and observing the effects, scientists will be able to understand how early primordial organisms may have functioned and evolved. There are also numerous applications for simplified genetic codes in laboratory experiments and clinical trials.

Before emergence of the current universal genetic code, primitive organisms that may have used only 19 amino acids could benefit from horizontal gene transfer, where cells transfer genetic material between one another. This is a key method used by bacteria to develop resistance to drugs. An organism with the current universal genetic code for 20 amino acids would have competitive advantages in its ability to synthesise proteins, but could not engage in genetic transfer with the rest of the population. Only when a suitably large gene pool of organisms with 20 amino acids is available could horizontal transfer occur between these life forms and they could then thrive. This implies that organisms with a simpler could be used as a barrier in , preventing new genetically modified strains from escaping to the natural world.

Explore further: Researchers discover new strategy germs use to invade cells

Related Stories

'Fishy' clue helps establish how proteins evolve

Jan 27, 2009

(PhysOrg.com) -- Three billion years ago, a "new" amino acid was added to the alphabet of 20 that commonly make up proteins in organisms today. Now researchers at Yale and the University of Tokyo have demonstrated ...

Model suggests how life's code emerged from primordial soup

Aug 07, 2009

(PhysOrg.com) -- In 1953, Stanley Miller filled two flasks with chemicals assumed to be present on the primitive Earth, connected the flasks with rubber tubes and introduced some electrical sparks as a stand-in for lightning. ...

Biologists uncover a novel cellular proofreading mechanism

Nov 11, 2011

(PhysOrg.com) -- To make proteins, cells assemble long chains of amino acids, based on genetic instructions from DNA. That construction takes place in a tiny cellular structure called a ribosome, to which amino acids are ...

Recommended for you

Researchers discover new strategy germs use to invade cells

Aug 20, 2014

The hospital germ Pseudomonas aeruginosa wraps itself into the membrane of human cells: A team led by Dr. Thorsten Eierhoff and Junior Professor Dr. Winfried Römer from the Institute of Biology II, members of the Cluster ...

Progress in the fight against harmful fungi

Aug 20, 2014

A group of researchers at the Max F. Perutz Laboratories has created one of the three world's largest gene libraries for the Candida glabrata yeast, which is harmful to humans. Molecular analysis of the Candida ...

How steroid hormones enable plants to grow

Aug 19, 2014

Plants can adapt extremely quickly to changes in their environment. Hormones, chemical messengers that are activated in direct response to light and temperature stimuli help them achieve this. Plant steroid ...

Surviving the attack of killer microbes

Aug 19, 2014

The ability to find food and avoid predation dictates whether most organisms live to spread their genes to the next generation or die trying. But for some species of microbe, a unique virus changes the rules ...

Histones and the mystery of cell proliferation

Aug 19, 2014

Before cells divide, they create so much genetic material that it must be wound onto spools before the two new cells can split apart. These spools are actually proteins called histones, and they must multiply ...

User comments : 0