RNA Evolution, RNA Function in RNA viruses and the Origin of Life

Essay by TheNemesis13University, Master'sA+, August 2006

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Plunging into the subject of RNA evolution and the origins of life coupled with viral evolution, is impossible without addressing a variety of parameters. This essay will concentrate on RNA evolution and the origins of life but unavoidably subjects as DNA evolution, amongst some, will be partially dealt with due to the strong relevance of their nature.

The RNA world hypothesis proposes that RNA was actually the first life-form on earth, later developing a cell membrane around it and becoming the first prokaryotic cell. The RNA World hypothesis is supported by the RNA's ability to store, transmit, and duplicate genetic information, just like DNA does. RNA can also act as a ribozyme (an enzyme made of ribonucleic acid). Because it can reproduce on its own, performing the tasks of both DNA and proteins (enzymes), RNA is believed to have once been capable of independent life. The RNA world hypothesis holds that in the primordial soup there existed free-floating nucleotides.

These nucleotides would regularly form bonds with one another, but the chains would often break apart because the change in energy was so low. However, certain sequences of base pairs have catalytic properties that actually lower the energy of their chain being created, causing them to stay together for longer periods of time. As each chain grew longer it attracted more matching nucleotides faster, causing chains to now form faster than they were breaking down.

These chains are proposed as the first, primitive forms of life. In an RNA world, different forms of RNA compete with each other for free nucleotides and are subject to natural selection. The most efficient molecules of RNA, the ones able to efficiently catalyze their own reproduction, survived and evolved, forming modern RNA.Competition between RNA may have favored the emergence of cooperation between different RNA...