The Survival of the Fittest... Molecule

by Alexandre Couto de Andrade

After Charles Darwin's “On the Origin of Species” was published in 1859, the way in which we human beings see ourselves has changed dramatically. Like Copernicus and Galileo before him, and like Freud (in spite of his pseudoscientific theories) and Einstein some decades later, Darwin started a scientific revolution. When it comes to answering the “big questions” of life and existence, few scientific theories or discoveries where so significant as “Evolution”.

Since then, numerous discoveries, made in various knowledge fields, have corroborated and increased our understanding of the theory of Evolution. Gregor Mendel, for instance, provided us with the knowledge necessary to understand how hereditary characteristics are transmitted from parents to offspring. In the beginning of the third decade of the 20^th century, Alexander Oparin developed a theory that explained how the early Earth atmosphere and primordial ocean created conditions to originate life. In 1952, the Miller-Urey experiment succeeded to synthesize amino acids in the conditions imagined by Oparin. Nowadays, the Genome Project is almost literally writing the history of life, offering an overwhelming quantity of evidence that confirm the theory of Evolution.

This week, an article published in the online edition of the journal Proceedings of the National Academy of Sciences (PNAS) describes the work of Sarah Voytek, Ph.D. , who created RNA molecules that evolve and compete with each other for resources. Her work not only confirms Oparin's idea that organic molecules can compete with each other, but also reveals the mechanisms of the resulting natural selection.

I transcribed below part of the article's abstract:

“Mixed populations of 2 different 'species' of RNA enzymes were made to compete for limited amounts of one or more substrates, with utilization of the substrate being necessary for amplification of the RNA. Evolution in the presence of a single substrate led to the extinction of one or the other enzyme, whereas evolution in the presence of 5 alternative substrates led to the accumulation of mutations that allowed each enzyme to exploit a different preferred resource”.

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