Before the dawn of life there was RNA

I suppose you've all heard about RNA; that it's related to the allmight DNA in one way or the other. What you might not know (if you're not into molecular evolution or just anything regarding evolution), is that once upon a time way back, before DNA started to function into something we define as life, there was another system of replicators highly dependent on RNA. Not much is known about this, but there's been some attempts to know more.

First, let's start with some basic RNA info (lots of chemical things here...skip if you're not interested or if it's just way too confusing). RNA stands for Ribo Nucleic Acid, and the only thing that differs it from a DNA (Deoxyribo Nucleic Acid) molecule is the presence of a hydroxyl group at one of the carbons. This, however, leads to differences in their chemical properties which is very, very important if we want life (as we know it) to exist. First of all, this changes the geometry (A-form instead of the general DNA B-form). Second of all, this -hydroxyl group can (if there's room) chemically attack a phosphodiester bond, so that the backbone of the RNA molecule is cleaved, as well as making RNA more prone to hydrolysis. RNA is usually present as shorter, single stranded chains of molecules, while DNA is usually in double stranded chains and is much longer. When you're not a molecular biology person, the most common thing to know about RNA (I suppose) is that it is the "in between state" when a gene is working. This is a basic rule of biology: DNA is transcribed into RNA that is translated into proteins. In addition, RNA can function as catalyst, acting in various ways. They do so by forming pairs, which are tightly and structurally packed with other pairs. Together, they can do powerful enzymatic activities. These properties have led scientists and general thinkers to hyothesize that RNA alone can function as both provider of information as well as the processor and
replicator of the information.

Image source: http://www.accessexcellence.org/RC/VL/GG/images/rna2.gif

Gerald Joyce at the Scripps Research Institute in La Jolla, California have just published some amazing results on this stuff. She, along with collegues (you're never alone in this buisness) made catalyst of
paired RNA. When all the necessary ingredients were supplied in a reaction mix, these were able to assembly eachother. These were mixed with building blocks of RNA, and due to the RNA catalyst not being the perfect version for their purpose, they mutated over time into new versions that were better than the originals, thus out-competing them. The outcome was highly dependent on the conditions in the reaction mixture.

In addition, these RNA catalysts were immortal, since they could replicate themselves indefinitely! This is one of the basic properties a life-information-containing molecule must have...

In my biased little brain, this leads me towards the conclusion (not scientific, just highly personal) that once again, evolution can be induced, it's molecular action can be proven, as well as that Darwinian theory is supported again (and again and again and again ad absurdum....eat that, beloved creationists!). Also, all tabula rasa inspired folks should be somewhat joyful, since this also proves that the environment is just as important as the genetic material, when looking at the outcome of it all. It's just great!

Links: http://www.nature.com/news/2009/090108/full/news.2009.5.html