Just like old times: Generating RNA molecules in water

American Society for Biochemistry and Molecular Biology ^ | Nov 20, 2009 | Unknown

[decimon]

Appearing in the Nov. 27, 2009, issue (Vol. 284, No. 48) of JBC

A key question in the origin of biological molecules like RNA and DNA is how they first came together billions of years ago from simple precursors. Now, in a study appearing in this week's JBC, researchers in Italy have reconstructed one of the earliest evolutionary steps yet: generating long chains of RNA from individual subunits using nothing but warm water.

Many researchers believe that RNA was one of the first biological molecules present, before DNA and proteins; however, there has been little success in recreating the formation on RNA from simple "prebiotic" molecules that likely were present on primordial earth billions of years ago.

Now, Ernesto Di Mauro and colleagues found that ancient molecules called cyclic nucleotides can merge together in water and form polymers over 100 nucleotides long in water ranging from 40-90 °C –similar to water temperatures on ancient Earth.

Cyclic nucleotides like cyclic-AMP are very similar to the nucleotides that make up individual pieces of DNA or RNA (A, T, G and C), except that they form an extra chemical bond and assume a ring-shaped structure. That extra bond makes cyclic nucleotides more reactive, though, and thus they were able to join together into long chains at a decent rate (about 200 hours to reach 100 nucleotides long).

This finding is exciting as cyclic nucleotides themselves can be easily formed from simple chemicals like formamide, thus making them plausible prebiotic compounds present during primordial times. Thus, this study may be revealing how the first bits of genetic information were created.

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From the JBC article: Generation of Long RNA Chains in Water" by Giovanna Costanzo, Samanta Pino, Fabiana Ciciriello and Ernesto Di Mauro

Article link: http://www.jbc.org/content/early/2009/10/02/jbc.M109.041905

Corresponding Authors: Ernesto Di Mauro, Department of Genetics and Molecular Biology, Sapienza University of Rome, Italy; Tel: +39.06.49912880, E-mail: Ernesto.dimauro@uniroma1.it

The American Society for Biochemistry and Molecular Biology is a nonprofit scientific and educational organization with over 11,900 members in the United States and internationally. Most members teach and conduct research at colleges and universities. Others conduct research in various government laboratories, nonprofit research institutions and industry. The Society's student members attend undergraduate or graduate institutions.

Founded in 1906, the Society is based in Bethesda, Maryland, on the campus of the Federation of American Societies for Experimental Biology. The Society's purpose is to advance the science of biochemistry and molecular biology through publication of the Journal of Biological Chemistry, the Journal of Lipid Research, and Molecular and Cellular Proteomics, organization of scientific meetings, advocacy for funding of basic research and education, support of science education at all levels, and promoting the diversity of individuals entering the scientific work force.

For more information about ASBMB, see the Society's Web site at www.asbmb.org.

[IronKros]

Here is a quick and dirty wiki write-up on a long term e-coli experiment which went on for over 20 years.

http://en.wikipedia.org/wiki/E._coli_long-term_evolution_experiment

[LiberConservative]

Indeed. Quite an interesting read. But it says little to support evolution. This is the saliant quote: ... the bacteria in each population are thought to have generated hundreds of millions of mutations over the first 20,000 generations, Lenski has estimated that only 10 to 20 beneficial mutations achieved fixation ...

And we are talking about one of the simplest lifeforms on the planet.

These mutations could very well have been in the genetic code of the bacteria for generations and repressed and appeared only after extreme numbers of generations. Furthermore, after all of these generations they are still only one genus or family: the e-coli bacteria. This is natural selection. Not evolution. There is a huge difference.

[IronKros]

Yes, this is scientific proof that natural selection is a fact. It is also amazing how many changes the e coli went through during the 20 years of the experiment (this was just a quick and dirty explanation).

Evolution has not bee proved in a lab. However, it does not need to be. There are mountains of evidence of evolution throughout our world.