Subscription link journal article via (doi:10.1038/nchem.1241), for those who want technical details.

Next up: the Opposable Thumbs On A Pole match!

AmorousRedDragon: Wow, that was a really good video. I got A's in biology and understood pretty well what i was seeing, but to see it in that detail was something else. The "walkers" on the microtubules legitimately blew my mind.

Indeed. Drew Berry is an amazing animator. You can see more of his work here ^{(^)}. The insulin video and the apoptosis video are quite excellent. The DNA replication video is also part of the Body Code video which also shows transcription and translation. Amazing stuff.

No Such Agency: Man, if I'm ever staying in a motel 1 billion years ago, I am definitely not touching the duvet cover, you know this stuff is gonna be all over it :P

Nah. By a billion years ago, things would have long since been DNA based, so you'll only have the conventional reasons for not touching the duvet cover. Now a hotel around 4.2 - 3.8 billion years ago, that would be another story...

GratuityIncluded: Has TNA been shown to act as an enzyme? No.

That should be the big kicker right there. One of the strongest arguments for the RNA world hypothesis is that RNA can act as both information storage and catalyst. Ribozymes (RNA "enzymes") are becoming better and better understood, and they make a great explanation for how the precursor system could evolve without protein coding genes and a way to translate them.

That way you have function and information storage evolving at the same time, rather than the chicken/egg problem of "which came first, the protein or the gene which encoded it?"

If RNA nucleosides can form abiotically (such as by the process linked above) and then concentrated in the presence of an energy source where they can polymerize (such as suggested by Martin & Russell 2003 ^{(^)} and elaborated upon by Koonin & Martin 2005 ^{(^)} [PDF]), then there is the possibility that ribozymes could form to act as catalysts in a variety of what we would consider biochemical reactions. Then, all you need is that one time where a self-replicating ribozyme forms, and the rest is history. Given that we are talking about ~300 million years between late heavy bombardment and the first fossil evidence of life, one would imagine that this is plenty of time for it to have happened, even with a very small probability.

Though they haven't actually produced full on self-replicating ribozymes in the lab yet, they are getting closer and closer, and when they show it is possible and perhaps even likely, then that will be a big support for the RNA world hypothesis.

Then the real kicker will be trying to figure out the origin of the translation system and the evolution of the genetic code. That remains one of life's biggest mysteries, though some interesting conceptual frameworks, such as this one ^{(^)}, have been proposed. However, if they puzzle that out, and thus the transition from RNA World to "RNP World", then carrying on from there to using DNA as information storage is not too difficult.

Approves.

SirRoderick: But a 4 carbon sugar is much more unstable than the 5 carbon sugar. Why the hell would that form on it's own accord? I expected them to say 6 carbon sugar.

That was my thought as well

SevenizGud: Stability is not the end-all of biochemistry. That's like arguing that all biologic poly-enes should have the double bonds in conjugation, because, you know, more stable.... So why doesn't it happen? Because other considerations prevail.

No, but the point is that a 4 carbon ring has greater bond stresses than a 5 or 6 carbon ring, and as such would require more energy to produce

/Be gentle on me, I can't remember that much from o-chem