Wednesday, February 26, 2014

#3 of 5 short stories on the Origin of Life - The First Language



Translating between languages can have some unexpected results
There is estimated to be an astounding 7,105 languages spoken by various people around the world today. Language is one of those few unique traits that distinguishes humans from other animals and the invention of human language is still a mysterious, yet critical development in the story of human civilization. Each of those languages allow for communication of ideas and gives shape to our thoughts. Of course, moving the ideas crafted in one language over to another between languages can result in an idea being lost in translation, as  use of Google translate can quickly show you - in this example, "I love Sweden" somehow translates as "I love Canada".

But the true first language was not human language, but cellular language. That first language is the universal language of all cellular life today. The time before the first hyperthermophilic cells started running around, the time before the last common ancestor to all known life is fascinating to consider. No one has had a bigger impact on this field of research than the late Carl Woese, who restructured the tree of life to its current 3 Domain format of Bacteria, Archaea and Eukarya. His article, On the Evolutionof Cells is fascinating to read and I recommend it to scientists and non-scientists alike.  

Woese describes a vision of early life, a form of life that would totally fail to pass the cellular/acellular definition of life today.  This pre-cellular life was not a simple, dumbed-down form of the cells we have today, but a complex network of self-repeating processes, a biochemical ecosystem that exchanged packets of information in the form of macromolecules between nodes of activity. We can’t know the exact rules of exchange within that living network, because the exchange of information was so promiscuous,  with biochemical "ideas" passed around so fluidly that there is no discernible pattern of descent left today. But that early biochemical network crossed an important threshold for life, for within that network a language was invented.

The Genetic Code, aka The First Language
That first language is the universal language of all cellular life today. Billions of years after its invention, this language is still spoken by cells in Mycoplasma genitalium, the blue whale, the honey mushroom or a human. There's little divergence from one organism to the next and certainly not at the level of 7,000 languages spoken by people today.  That one molecular language was the symbolic representation of amino acids in 3 letter words of RNA, through a combination of chemical specificity and some arbitrary connections.  The process of using the language is called translation or sometimes casually referred to as The Genetic Code. Some version of the codon table pictured is a staple on molecular biology exams, and in area of study for synthetic biology as we try to develop new ways for using the chemical language that got life started.

Next up is #4 The Singularity (x 3)

 Back to #1 The cellular/acellular divide and #2 Magma oceans andmarauding asteroids
 

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2 comments:

  1. UnknownApril 21, 2014 at 9:04 PM

    I understand that this complex network of information exchange let to the language of translation which evolved to the three branches of life today. However I am a little confused because if it started from large exchange of macromolecules, what made the macromolecules if translation came second?

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  2. AnonymousMay 20, 2014 at 9:32 PM

    If pre-cellular life is not a "simple, dumbed-down form of the cells we have today," it is interesting how we know more about the more evolved forms than the complex network from which they descended. To take a philosophical approach, it is nice to think about how the communication between cells to be the most basic form of universal language; a language that everyone knows how to understand without having conscious knowledge of that fact. This goes along with the fact that non-word based languages, like music or visual art, can create bridges between different people. In this sense, the language we possess by simply living is a uniting factor.
    - Laura Fong

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