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RNA is much simpler to manufacture than DNA as it only has
a single strand. It is possible that the first life on earth was
RNA based which later evolved into DNA based life. What we
would like to know is how the first self-replicating strands of
RNA came about.
Experiments show that several silicate minerals can act as catalysts to enable complex, organic material to self assemble.
These inorganic molecules have a particular mineral structure
and the oldest zircon grains confirm that these were abundantly available on Earth about 4.4 bn years back. Moreover,
these silicate minerals contain layers of molecules to which
organic molecules can easily attach to. When organic molecules attach to the mineral surface in this way, they can be
forced into such close proximity that they react with each
other to form long chains of molecules.
Laboratory experiments have confirmed that natural processes such as this can easily manufacture strands of RNA up
to a few dozen bases in length. Scientists have discovered an
RNA strand only 5 bases long which can act as a ribozyme.
In this way it is possible that simple ribozymes could have
been formed, which then acted as a catalyst for forming more
complex self – replicating RNA molecules.
ICY SCIENCE | QTR 1 2014