Sunday, February 26, 2017

Hints to the Possibility of a Cold Origin of Life

When asked to imagine the origin of life, many things come to mind. Some picture a creator, others a warm primordial soup teeming with organics or a chemically rich environment near a deep sea hydro-thermal vent, while others see it hatching a ride to earth on a comet or asteroid. Yet, most don't picture a cold, icy world fostering the origins of life. Why?

Traditionally, the cold just seems dull or uninviting - it does not appear to be a dynamic situation, it seems rather frozen, sometimes barren and hostile, sitting mostly unchanged throughout time. But guess what? Taking the words of Elsa, the cold never bothered RNA anyway.

More specifically, low temperatures enhance ribozyme activity and catalytic ability - improving RNA polymerization. This does seem somewhat strange though - how would lowering the temperature enhance catalytic ability? We know that the rate of a chemical reaction increases with temperature. However, the low temperature and the eutectic properties of water (waters ability to form a water ice emulsion) strikes a balance between the thermodynamics and kinetics of the RNA polymerization reaction by the ribozyme.

Cold temperatures (particularly cyclic cold conditions where we have freezing and thawing) also drives the formation of complex ribozymes. Now we have a mechanism for the formation of ribozymes as well as a mechanism for the enhancement of there catalytic ability. But why does all this matter? Many researchers now believe that an RNA world was a precursor to the development of the biotic world, RNA being able to self-replicate and catalyze reactions - providing a mechanism upon which different selective pressures could act upon it. While RNA does not tell the whole story, it does give us a mechanism by which genetic information storage could have evolved - as well as how the coupling of genotype and phenotype may have taken place.

Life on earth may or may not have had a cold origin, but this information provides us with some useful insights and ideas that we can draw on when postulating about the nature of the origin of life on our planet and perhaps others. Who knows? Maybe this is just right mechanism for describing how life may have potentially taken hold on some of the icy Jovian moons, the cold subsurface oceans the perfect place for fostering the complex development of an RNA world and the subsequent develop of alien - or not so alien - life.

If you want to read more about RNA and its relationship with the cold, here are some interesting reads:
http://www.nature.com/nchem/journal/v5/n12/full/nchem.1811.html
http://www.nature.com/nchem/journal/v5/n12/full/nchem.1781.html#ref11
http://www.nature.com/nchem/journal/v7/n6/full/nchem.2251.html#references

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