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    (Original post by frost105)
    I love the idea that all humans can be traced back to one common ancestor through our mitochondria.
    This is a quote from Newsweek in 1998:

    "Eve was more likely a dark-haired, black-skinned woman, roaming a hot savannah in search of food. She was as muscular as Martina Navratilova, maybe stronger; she might have torn animals apart with her hands."

    So for any racist person who believes white people are better than black people-once upon an evolutionary tale we were once all dark skinned!

    If this interests you, read up on Bryan Sykes.
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    (Original post by Ben.S.)
    PNA!

    Ben
    hehe, although there is no direct evidence for a pre-RNA world, peptide nucleic acid and RNA well could have co-existed until RNA took the upper hand.
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    (Original post by Fluffy)
    If this interests you, read up on Bryan Sykes.
    i read the seven daughters of eve on the train, this weird science guy started talking to me at paddington and i had to move carriages.
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    (Original post by timeofyourlife)
    i read the seven daughters of eve on the train, this weird science guy started talking to be at paddington and i had to move carriages.
    Bryan is a fellow at my college - nice guy, but scary after a few too many glasses of wine

    His car reg plate is D7 EVE :rolleyes:
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    (Original post by Fluffy)
    Bryan is a fellow at my college - nice guy, but scary after a few too many glasses of wine

    His car reg plate is D7 EVE :rolleyes:
    :rolleyes: could be worse, you could be going to dinner with Stryer

    Edit: I'm not sure whether he's dead or not so that could be an experience in itself!
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    (Original post by timeofyourlife)
    hehe, although there is no direct evidence for a pre-RNA world, peptide nucleic acid and RNA could have well co-existed until RNA took the upper hand.
    I imagine that that would have to be the case - how else could peptides and nucleic acids become so initially intertwined?

    Ben
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    (Original post by timeofyourlife)
    :rolleyes: could be worse, you could be going to dinner with Stryer
    Or Alberts...

    Ben
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    (Original post by timeofyourlife)
    :rolleyes: could be worse, you could be going to dinner with Stryer

    God! How painful does that sound!!!

    (Original post by timeofyourlife)
    Edit: I'm not sure whether he's dead or not so that could be an experience in itself!
    Musty, I would have thought
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    (Original post by Ben.S.)
    I imagine that that would have to be the case - how else could peptides and nucleic acids become so initially intertwined?

    Ben
    indeed. otherwise known as the 'rna world hypothesis' or something. Dr. fluffy will know!
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    (Original post by timeofyourlife)
    indeed. otherwise known as the 'rna world hypothesis' or something. Dr. fluffy will know!
    Something like that. I'm going to have to do cell biology again this year and I really don't want to!

    Ben
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    (Original post by Ben.S.)
    I imagine that that would have to be the case - how else could peptides and nucleic acids become so initially intertwined?

    Ben
    The science:

    Nonenzymatic template-directed polymerization reactions have been achieved in systems consisting of homochirally pure monomers activated by simple organic chemical groups, supporting the possibility of an ancestral protein-free nucleic acid replicating system.

    Ribonucleic acid appears to be unique among biomolecules not only because of its dual ability to serve as repository of genetic information and to perform catalytic activities, but also because of its central role in several biological processes.

    However, RNA is a complicated, fragile polymer, and the spontaneous emergence of ribozyme-catalysed RNA replication from the primitive soup is difficult to envision. The initial optimism surrounding the possibility of an RNA world has been challenged by an increasing awareness that current evidence does not support the abiotic synthesis of RNA molecules or that of its monomeric constituents. The prebiotic formation of ribonucleotides faces major challenges, which include the lack of a prebiotic source of high-energy phosphates and the problems associated with the synthesis and accumulation of ribose. The formose reaction, traditionally invoked to account for the presence of ribose on the primitive Earth, in fact yields a complex array of over 40 different sugars, of which equal amounts of l- and d- ribose are relatively minor components. It is difficult to see how ribose could be enriched from this mixture, or how it could be preferentially synthesized over the three other possible pentoses and eight hexoses.

    There may be variations of the formose reaction and geochemical settings in which ribose can be produced preferentially. By condensing glycoaldehyde phosphate with formaldehyde under mild neutral conditions and in the presence of minerals, it is possible to synthesis ribose 2,4-bisphosphate highly selectively. This ribose derivative, which can form a six-membered phosphorylated ring – i.e. a pyranose diphosphorylated sugar – can be polymerized into a nucleic acid analogue with a ribopyranose phosphate backbone instead of the usual ribofuranose found in RNA.

    However, ribose, ribose 2,4-bisphosphate and deoxyribose, and other sugars, are thermolabile compounds that decompose so rapidly that their presence in the prebiotic environment has been questioned. Thus, although RNA molecules remain one of the best working models for study of the early stages of biological evolution, it is possible that RNA was preceded by an as yet uncharacterized replicating genetic polymer. Several different candidates for this pre-RNA world have been suggested, including the so-called peptide nucleic acids (PNAs), which are nucleic acid-like molecules that have a protein-like backbone to which nucleobases are attached by an acetic acid.
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    (Original post by spk)
    The science:
    remember people, we are but mere survival machines for the rarely altruistic immortal coils that form our being :rolleyes:
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    (Original post by timeofyourlife)
    indeed. otherwise known as the 'rna world hypothesis' or something. Dr. fluffy will know!
    Spk is better placed!
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    (Original post by Ben.S.)
    Something like that. I'm going to have to do cell biology again this year and I really don't want to!

    Ben

    what degree are you doing?
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    (Original post by Fluffy)
    Spk is better placed!
    hehe, it's probably an extract from your dissertation.
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    (Original post by timeofyourlife)
    hehe, it's probably an extract from your dissertation.

    Lol!

    I get distressed when talking Gilbert - I keep getting annoying musical sound tracks stuck in my head - garrrggghhh! Too late!!
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    (Original post by timeofyourlife)
    what degree are you doing?
    BA/MA or something - actually, that's a very good question: I have no idea!

    Ben
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    (Original post by timeofyourlife)
    hehe, it's probably an extract from your dissertation.
    No, I adapted it from an article on 'Prebiotic Chemistry' in the Nature Encyclopedia of Life Sciences (www.els.net).

    For the record, my first degree was Biochemistry, and I'm about to start Medicine.
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    (Original post by timeofyourlife)
    remember people, we are but mere survival machines for the rarely altruistic immortal coils that form our being :rolleyes:
    That is so from a Dawkins book.
    J
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    (Original post by Gnostic XXX)
    I find your logic to be flawed. We can trace our ancestry back to ape-like creatures and further back to amino acids but that doesn’t mean apes and amino acids are “equal” to humans.
    No, but the fact that there are still black people in the world would suggest that.

    Ben
 
 
 
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