The World's Fair

Well, who would have thought?

RNA makes the cover of the Economist. Mind you, I don't think its importance is that surprising to folks already in the field, since RNA has always garnered a certain amount of respect as a macromolecule of note and curios.

This can, more or less, be boiled down to number of special points to consider:

Firstly, RNA is indeed a molecule composed of a 4 nucleotide code. In this respect, it has the same combinatorial ability as our stalwart DNA (you know, the Human Genome, etc), which is awesome for both its scope, but also in its inherent simplicity (just 4 building blocks can do all this!). However RNA is also noteworthy in its sugar backbone - this is the difference between deoxyribose and ribose. This otherwise small change allows RNA to have an additional crucial feature - that is, it is structurally flexible.

This is point number two. Whereas DNA is often confined to a relatively limited set of thermodynamically favourable shapes (think double helix for example), RNA molecules are privy to some pretty fancy structures. In this light, RNA is kind of comparable to proteins, in that not only can the molecule act as a code keeper, it can also take on specific shapes and therefore have functions as defined by these shapes. Many examples of this abound, including catalytic RNA's and the like.

As an example of this feature, many papers have been published on a strategy known as directed evolution. Here, the premise essentially submits that you can make RNA molecules with useful functions,by randomly producing RNA sequences, and then selecting for sequences that "do" stuff. With this pool, you can then reselect, with more stringency, and the premise is that one can begin to zone in on "best" or "most evolved" sequences that have the best capabilities. All the while, you can use the relative ease of RNA synthesis to quickly provide or amplify these pools. But I digress...

The point is, is that RNA turns out to have a "best of both worlds" situation with desirable features from both the DNA and protein camp. This is also why, some folks often talk of an "RNA world" as RNA is a good candidate for one of the earliest biological molecules to have come about (we talking about the origin of life stuff here).

As well, the real and/or potential capabilities of RNA molecules also speaks to why there are so many tough, hardy, down right difficult to deal with molecules that simply want to destroy it - molecular biologists know these pain in the asses, these RNases well. These degraders of RNA really are a piece of work - for example, you need to bake them in an oven for over 4 hours over 250C just to knock them out- they're that tough! The point is: if nature has gone to so much effort to have things that do their darndest to get rid of them, then they must be important.

And important they are. The articles in the Economist largely refer to the growing number of specialized RNAs (often smallish in size) that have hit the biological scene in the last decade or so, many of which have amazing capabilities that are interesting in their own right, but also of potential use particularly in the health arena.

Anyway, with this increasing coverage on the molecule, it'll also be interesting to see how folks who follow the Intelligent Design camp react, more so if they also consider the origin of life angle.

Besides, as Lena was astute enough to point out, perhaps RNA is just so cool that it's the sort of thing that aliens brought with them. I mean, they do say a picture is worth a thousand words...