Complex mistakes in protein chemistry

Evolution by natural selection works by favouring different traits in a population. But where do these differences come from?

Well obviously there are genetic mutations, or random changes in the DNA, some of which can be beneficial and win out in natural selection. But new research has shown how errors in proteins can also lead to complexity.

Diagram of the primary, secondary, tertiary and quaternary structure of proteins (Image courtesy National Human Genome Research Institute, via Wikimedia Commons)

Proteins are quite complex molecules. They’re constructed from chains of amino acids, the combination of which is encoded in the DNA. But the way they join and fold up determines the way they interact with other chemicals in the body.

Although now it seems that small changes in the way they fold can make it possible for the proteins to combine in more complex ways, without necessarily causing much difference in adaptation. If the population is small and the changes don’t seriously affect the way the proteins function, they can quickly spread throughout the group. And this then gives more complexity for natural selection to play its games.

As one of the researchers, Ariel Fernández, said:

“Natural designs are often one notch more sophisticated than the best engineering. This is another example: Nature doesn’t change the molecular machinery, but somehow it tinkers with it in subtle ways through the wrapping.” (Science Daily)

Fernández A & Lynch M 2011, “Non-adaptive origins of interactome complexity”, Nature, doi:10.1038/nature09992