RNA enzymatic activity supports RNA world theory
21 Nov '14 20:303 editshttp://phys.org/news/2014-11-hurdles-rna-world.html
"...Astrobiologists have shown that the formation of RNA from prebiotic reactions may not be as problematic as scientists once thought.
One hypothesis for the origin of life on Earth includes a period known as the 'RNA World.' In this scenario, ribonucleic acid (RNA) formed from non-biological reactions before being incorporated into life's first cells.
The study presents a proof-of-concept system that could overcome previously sited challenges to the RNA World hypothesis, and was published in the Journal of the American Chemical Society (JACS).
Today, RNA in cells is best known for its role in transferring information in cells, ultimately effecting how genes from DNA are expressed. However, studies have shown that RNA can also play an important role in catalyzing reactions in cells that are necessary for life – in a way similar to proteins that are known as enzymes.
The multiple talents of the RNA molecule make it a prime candidate for use in Earth's first cells. RNA may have provided early life with a means for storing genetic information, and it also could have pushed important reactions along before enzymes were readily available.
Life relies on a complex dance of chemical reactions inside cells. These reactions require a variety of different molecules. A molecule that can perform multiple functions (like RNA) could have been extremely useful in the early stages of life's development, and at a time when the huge variety of biological molecules we see today had yet to evolve.
..."
Basically, the implication of this is that the evidence clearly implies that the first life could have functioned without protein-based enzymes (nor DNA for that matter ) but had RNA-based enzymes instead. Thus this solves the problem of which came first; RNA or protein; the first life had, according to this reasonable theory, only simple RNA and no protein (nor DNA for that matter ).
Note that I call it "theory" in the above rather than "hypothesis" because, in my opinion, there is now good evidence for it as the alternatives would seem to me to be significantly less probable.
Obviously, it is reasonable to assume that the more complex DNA evolved from the very similar RNA sometime later and probably after complex proteins evolved.
"...Astrobiologists have shown that the formation of RNA from prebiotic reactions may not be as problematic as scientists once thought.
One hypothesis for the origin of life on Earth includes a period known as the 'RNA World.' In this scenario, ribonucleic acid (RNA) formed from non-biological reactions before being incorporated into life's first cells.
The study presents a proof-of-concept system that could overcome previously sited challenges to the RNA World hypothesis, and was published in the Journal of the American Chemical Society (JACS).
Today, RNA in cells is best known for its role in transferring information in cells, ultimately effecting how genes from DNA are expressed. However, studies have shown that RNA can also play an important role in catalyzing reactions in cells that are necessary for life – in a way similar to proteins that are known as enzymes.
The multiple talents of the RNA molecule make it a prime candidate for use in Earth's first cells. RNA may have provided early life with a means for storing genetic information, and it also could have pushed important reactions along before enzymes were readily available.
Life relies on a complex dance of chemical reactions inside cells. These reactions require a variety of different molecules. A molecule that can perform multiple functions (like RNA) could have been extremely useful in the early stages of life's development, and at a time when the huge variety of biological molecules we see today had yet to evolve.
..."
Basically, the implication of this is that the evidence clearly implies that the first life could have functioned without protein-based enzymes (nor DNA for that matter ) but had RNA-based enzymes instead. Thus this solves the problem of which came first; RNA or protein; the first life had, according to this reasonable theory, only simple RNA and no protein (nor DNA for that matter ).
Note that I call it "theory" in the above rather than "hypothesis" because, in my opinion, there is now good evidence for it as the alternatives would seem to me to be significantly less probable.
Obviously, it is reasonable to assume that the more complex DNA evolved from the very similar RNA sometime later and probably after complex proteins evolved.
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