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The RNA world theory posits that RNA performed the duties of
catalysis (ribozymes) & information storage during a very early stage of
life. This theory simplifies the origin of life by proposing a
relatively uncomplicated replicating intermediate but it also implies
that the RNA world then transitioned to the DNA-RNA-protein world which
included the ‘genetic takeover’ of information storage by DNA. In the
first part of my talk I will discuss the prebiotic evolutionary
advantages of transferring genetic information from RNA to DNA (i.e.
using DNA as the genetic material). Our results suggest that the
'genetic takeover' may have been driven by a combination of increased
chemical stability, increased genome size, and irreversibility.
In the second part of my talk, I will briefly discuss our ongoing work
on synthesis of informational polymers by guided polymerization
reactions that might have occurred on prebiotic earth. Amphiphilic
lipids are known to spontaneously self-assemble to form orderly
structures that concentrate reactants (like mononucleotides) in their
liquid crystalline matrices, yet also permit diffusional mobility. These
lamellae enhance reaction rates by promoting self-aggregation of
reactants in configurations that promote polymerization and prevent side
reactions. Ribonucleotides form ordered 2-dimensional films between the
lamellae where in the conditions produce a chemical potential that
reduces water activity and shifts reaction equilibrium towards
condensation, thereby overcoming entropic barriers. This can promote the
formation of complex mixtures of oligomers under prebiotic conditions. I
will present some of our preliminary data in this regard |