Alternative to RNA-first theory for life on Earth– some comments and a link from NASA.gov site


amino acid mirror images

from Wikipedia

Proteins first vs RNA first ?–perhaps the energetics would prove unfavorable for RNA-first?  Stay tuned. . .

For a number of years, the paradigm of life’s origins was that RNA came first. Part of the reason for this paradigm was its propensity for self-reactivity. Current findings seem to up-end the paradigm with a major finding by Dr. Michael Blaber of Florida State University. Here is the link from the NASA astrobiology site:

http://www.astrobio.net/pressrelease/5447/new-study-points-to-proteins-and-salt-for-lifes-origin

DESCRIPTION of FIGURE:

Directly from Wikipedia: “Amino Acid Chirality chirality with hands from http://www.nai.arc.nasa.gov/ A “chiral” molecule is one that is not superimposable with its mirror image. Like left and right hands that have a thumb, fingers in the same order, but are mirror images and not the same, chiral molecules have the same things attached in the same order, but are mirror images and not the same. Although most amino acids can exist in both left and right-handed forms, Life on Earth is made of left-handed amino acids, almost exclusively. No one knows why this is the case. However, Drs. John Cronin and Sandra Pizzarello have shown that some of the amino acids that fall to earth from space are more left than right. Thus, the fact that we are made of L amino acids may be because of amino acids from space. Why do amino acids in space favor L? No one really knows, but it is known that radiation can also exist in left and right-handed forms. So, there is a theory called the Bonner hypothesis, that proposes that left-handed radiation in space (from a rotating neutron star for example) could lead to left-handed amino acids in space, which would explain the left-handed amino acids in meteorites. This is still speculative but our paper makes it much more plausible. In fact, this observations was one of the main reasons why we pursued this research. Although there were theories about how the amino acids could form in space in the ice, no one had shown that it was viable to make amino acids this way, until now.”

 

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14 thoughts on “Alternative to RNA-first theory for life on Earth– some comments and a link from NASA.gov site

  1. Emily L. Williams

    Very interesting, another fascinating possibility leading to biochemical chirality. Although I personally favor the concept of rock formations providing a chiral-inducing plane on which proto-life can grow and develop– but considering none of us were there at the time life started, I guess we can only speculate and rate those circumstances most likely to produce chiral biochemicals, of which there are probably a fair few alternatives. I kind of doubt we’ll ever truly “know”. Thanks for sharing! 🙂

    Reply
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