Yazata
Valued Senior Member
The NSF/NASA Center for Chemical Evolution at Georgia Tech has published some exciting news for origin of life studies in the April 25 'Nature Communications'.
This relates to the 'RNA world' hypothesis, the widely shared idea that RNA preceeded DNA as a proto-biological chemical replicator and that the earliest evolution of the genetic code took place in RNA.
Speculation these days is that RNA might have had its own chemical replicator precursers, that no longer exist in present-day biology. These are termed 'proto-RNA' and have similar but different nucleotides.
The new development announced today involves barbituric acid and melamine in place of RNA's familiar adenine and uracil. Apparently it's believed that barbituric acid and melamine might have been abundant in the early prebiotic Earth.
Experiment shows that barbituric acid and melamine combine with the sugar ribose very readily. Not only that, they pair with each other with hydrogen bonds to form something very similar to Watson and Crick base-pairs in a ladder structure.
And perhaps most significantly, this proto-RNA polymerizes in water to form long chains. One of the biggest problems with the RNA-world origin-of-life theorizing is that regular RNA won't seem to polymerize in water. But here we have something that might be an RNA precurser that does.
There are still big gaps in the story, most notably how and why adenine and uracil took the place of barbituric acid and melamine. But I think that this is a big step towards understanding how life might conceivably have orignated.
http://phys.org/news/2016-04-links-brewed-primordial-puddles.html
This relates to the 'RNA world' hypothesis, the widely shared idea that RNA preceeded DNA as a proto-biological chemical replicator and that the earliest evolution of the genetic code took place in RNA.
Speculation these days is that RNA might have had its own chemical replicator precursers, that no longer exist in present-day biology. These are termed 'proto-RNA' and have similar but different nucleotides.
The new development announced today involves barbituric acid and melamine in place of RNA's familiar adenine and uracil. Apparently it's believed that barbituric acid and melamine might have been abundant in the early prebiotic Earth.
Experiment shows that barbituric acid and melamine combine with the sugar ribose very readily. Not only that, they pair with each other with hydrogen bonds to form something very similar to Watson and Crick base-pairs in a ladder structure.
And perhaps most significantly, this proto-RNA polymerizes in water to form long chains. One of the biggest problems with the RNA-world origin-of-life theorizing is that regular RNA won't seem to polymerize in water. But here we have something that might be an RNA precurser that does.
There are still big gaps in the story, most notably how and why adenine and uracil took the place of barbituric acid and melamine. But I think that this is a big step towards understanding how life might conceivably have orignated.
http://phys.org/news/2016-04-links-brewed-primordial-puddles.html