Theoretical origin of life; a review of RNA first (Introduction)

by David Turell , Friday, June 26, 2015, 15:39 (3438 days ago) @ David Turell

This is an apologetic view of using the RNA first theory as still the best available. The author points out all the difficulties, and rules out proteins first theory as better. He titles his article as "the worst theory of the start" of life, except for all the others!-http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3495036/-"Abstract: The problems associated with the RNA world hypothesis are well known. In the following I discuss some of these difficulties, some of the alternative hypotheses that have been proposed, and some of the problems with these alternative models. From a biosynthetic - as well as, arguably, evolutionary - perspective, DNA is a modified RNA, and so the chicken-and-egg dilemma of “which came first?” boils down to a choice between RNA and protein. This is not just a question of cause and effect, but also one of statistical likelihood, as the chance of two such different types of macromolecule arising simultaneously would appear unlikely. The RNA world hypothesis is an example of a ‘top down' (or should it be ‘present back'?) approach to early evolution: how can we simplify modern biological systems to give a plausible evolutionary pathway that preserves continuity of function?