De novo evolution of Nylonase?

[sfmatheson]

This has been discussed before here on the forum:

Biological Information and Intelligent Design: evolving new protein folds

You’re welcome. I think that paper was groundbreaking because it showed how prokaryotes can “invent” new genes without the benefit of extra DNA. The phenomenon is now called “overprinting” and involves frame shifts as Ohno found in 1984. According to this recent paper, we now have four known examples of this. Overprinting shows how easy it is (in principle) for new genetic information to arise through small changes, even in environments like bacterial genomes where there is almost no unused gene…

For a technical discussion of the origins of the brand-new nylonase gene, see the Discussion section of this somewhat recent paper:
http://www.jbc.org/content/280/47/39644.long
I think I understand why there is some confusion about whether the gene is an example of de novo evolution (a frameshift can create a not-previously-used protein sequence, to answer @jpm question above) versus “merely” a repurposing of an existing sequence via “minor” mutational change. The nylon-degrading enzymes that we’re considering form a little family of enzymes, some of which seem to be derivatives of previously existing enzymes. (Side note: that’s a great example of evolution and by itself makes all the talk about “information” look silly.) But there’s an enzyme in the family that seems to have no physical relationship to the others. That’s the new one that we’re talking about, and the topic of the JBC paper I mention above. BTW, the JBC paper is about a further derivative of that new enzyme, so don’t be confused by the abstract which could be misinterpreted to be about minor mutational changes to an existing nylonase.