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The RNA world hypothesis is a theory which proposes that a world filled with RNA (ribonucleic acid) based life predates current DNA (deoxyribonucleic acid) based life. RNA, which can store information like DNA ''and'' Catalyze reactions like Protein s ( Enzyme s), may have supported cellular or pre-cellular life. Some theories as to the Origin Of Life present RNA-based catalysis and information storage as the first step in the evolution of cellular life. The RNA world is proposed to have Evolved into the DNA and protein world of today. DNA, through its greater chemical stability, took over the role of Data Storage while protein, which is more flexible in catalysis through the great variety of amino acids, became the specialized catalytic molecules. The RNA world hypothesis suggests that RNA in modern cells, in particular RRNA (RNA in the Ribosome which Catalyze s Protein production), is the evolutionary remnant of the RNA world. HISTORY The phrase "RNA World" was first used by Nobel laureate Walter Gilbert in 1986, in a commentary on recent observations of the catalytic properties of various forms of RNA.1 However, the idea of independent RNA life is older and can be found in Carl Woese 's ''The Genetic Code''2. In 1963 (five years earlier), the molecular biologist Alexander Rich , of the Massachusetts Institute Of Technology , had posited much the same idea in an article he contributed to a volume issued in honor of Nobel-laureate physiologist Albert Szent-Györgyi . PROPERTIES OF RNA The properties of RNA makes the idea of the RNA world hypothesis conceptually possible, although its plausibility as an explanation for the origin of life is debated. RNA is known to form efficient catalysts and its similarity to DNA makes its ability to store information clear. A slightly different version of the hypothesis is that a different type of Nucleic Acid , termed ''pre-RNA'', was the first one to emerge as a self-reproducing molecule, to be replaced by RNA only later. Such nucleic acids are sometimes more easily produced and/or polymerized under pre-biotic conditions. Suggestions for such nucleic acids include PNA , TNA or GNA 3 |
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