Well, here is what Woese has to say about RNA world.
| Power shortage Evolutionary biologist Carl Woese of the University of Illinois says the genetic evidence contradicts the RNA world theory. And if that weren't bad enough, he also argues that the RNA world scenario is fatally flawed because it fails to explain where the energy came from to fuel the production of the first RNA molecules, or the copies that would be needed to keep the whole thing going. In test-tube RNA worlds, the elongating RNA molecules are fed artificially "activated" nucleotides, boosted with their own tri-phosphate bond to ensure that they come with an energy supply. In nature, such molecules only exist inside cells, and they have never been created in a Miller-type experiment. "The RNA world advocates view the soup as a battery, charged up and ready to go," Woese complains. On the primordial Earth, that energy had to come from somewhere, and it had to be coupled to production, or else it would quickly disappear into the ether. In Woese's view, the critical step that ultimately spawned life was not a few stray RNA molecules, but the emergence of a biochemical machine that transformed energy into a form that was instantly available for the production of organic molecules. |
A self replicating molecule is: amino adenosine triacid ester. Who knows if it was the first in existence? Lee etal, in a 1996 Nature paper (vol 382) discovered a self-replicating peptide.
Recently, a paper was published in the Journal of the Americal Chemical Society by Isaac and Chmielewski (2002), vol 124 p 6808. There, they discuss the cycle of reproduction for one of a peptide chain called E1E2. They are able to get this particular chain to catalyze at an amazing rate, approaching that of natural enzymes, and all at condition found in nature.
If you want a good review article on abiogenesis that isn't too old, you can try the paper by McClendon, 1999, Earth Science Reviews, 47, pg 71-93. It is a review of the remaining lines of research I haven't covered, such as the earliest known fossil, theories on the origin of the earth, and the environment of the first billion years. It talks about models of survivability of organic matter if it falls to the Earth in the form of comets, and, of course, it discusses chemical simulations of life a-la Miller-Urey. This paper is quite good, and covers a lot of ground at a good intermediate level. I suggest everyone read it if they haven't already. You may be able to down load it from here, if you search for it.
So, Andrew, I've now shown you research on both ends of the life from lifelessness barrier. Each line of research advances at a pretty good rate (we did not know of a self replicating molecule 13 years ago, now we know of several). Do you think that the evidence for abiogenesis is more or less than that for any other theory? Could you show us that evidence?