RNA world easier to make : Nature News - The Diigo Meta page

• 29 May 14
  

  vmancha
  • RNA world easier to make
  • An elegant experiment has quashed a major objection to the theory that life on Earth originated with molecules of RNA.
  • The feat, never performed before, bolsters the 'RNA world' hypothesis
  • This is extremely strong evidence for the RNA world
  • We don't know if these chemical steps reflect what actually happened, but before this work there were large doubts that it could happen at all
  • “We had a suspicion there was something good out there, but it took us 12 years to find it.
  • "What we have ended up with is molecular choreography, where the molecules are unwitting choreographers."
  • The flaw with this kind of research is not in the chemistry. The flaw is in the logic — that this experimental control by researchers in a modern laboratory could have been available on the early Earth," says Robert Shapiro, a chemist at New York University
  • "My ultimate goal is to get a living system (RNA)
  • "They're perfectly entitled to disagree with us. But having got experimental results, we are on the high ground," says Sutherland
  • "We might come up with something so coincidental that one would have to believe it,

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• 16 May 09
  

  rna chemia biologia abiogeneza exportedfromdelicious

• 15 May 09
  

  Mike Chelen

  rna

  • John Sutherland and his colleagues from the University of Manchester, UK
  • ribonucleotide
  • building block of RNA
  • 'RNA world' hypothesis, which suggests that life began when RNA, a polymer related to DNA that can duplicate itself and catalyse reactions
  • strong evidence for the RNA world
  • Donna Blackmond, a chemist at Imperial College London.
  • RNA polymer is a string of ribonucleotides
  • three distinct parts: a ribose sugar, a phosphate group and a base
  • chemists had thought the subunits would probably assemble themselves first, then join to form a ribonucleotide
  • efforts to connect ribose and base together have met with frustrating failure
  • researchers have now managed to synthesise
  • ribonucleotides
  • remedy is to avoid producing separate ribose-sugar and base subunits
  • makes a molecule whose scaffolding contains a bond that will
  • atoms are then added around this skeleton
  • be the key ribose-base connection
  • final connection is to add a phosphate group
  • influences the entire synthesis
  • acting as a catalyst, it guides small organic molecules into making the right connections
  • What we have ended up with is molecular choreography
  • objectors to the RNA-world theory say the RNA molecule as a whole is too complex to be created using early-Earth geochemistry
  • flaw is in the logic — that this experimental control by researchers in a modern laboratory could have been available on the early Earth
  • Robert Shapiro, a chemist at New York University
  • early-Earth scenarios
  • heating molecules in water, evaporating them and irradiating them with ultraviolet light
  • results showing that they can string nucleotides together
  • ultimate goal is to get a living system (RNA) emerging from a one-pot experiment
  • need to know what the constraints on the conditions are first
  • Shapiro sides with
  • another theory of life's origins
  • because RNA is too complex to emerge from small molecules, simpler metabolic processes
  • eventually catalysed the formation of RNA and DNA

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