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RE: The Central Dogma Theory 2: DNA Replication
So what came first: The DNA or the parts it codes for, which is needed to create DNA, store it and express it into living things ? :)
Nice post thanks
So what came first: The DNA or the parts it codes for, which is needed to create DNA, store it and express it into living things ? :)
Nice post thanks
Interesting question - look up RNA world hypothesis. In short it postulates that the most likely first biomolecule to exist and auto replicate was in fact RNA/Ribozymes as it is able to independently replicate, catalyse simple chemical reactions and interact with its environment under certain forms.
This is what we call autocatalytic RNA or a Ribozyme. This idea has even been tested in the lab, and they have been able to guide the evolution of autocatalytic RNA to make it more and more prone to auto replication - eventually it just starts evolving itself and producing new features through mutation which may or may not favour survival.
Check out this article from Science for more information: http://science.sciencemag.org/content/323/5920/1436.full
I´ve read into this earlier and i think it falls short in the same way. RNA would never self assembly and the nucleotides is made by living organisms so it had nothing to be build upon. Ribosomal RNA would never self assembly its to complex and it would have no environment to live in, he earth was hot as fuck! No cell membrane or even lipids which could make up membranes.
It would take a lot for life to kick start and nothing in science got a clue of how it started, i find it amazing that life exists against all odds, or does it :) ?
Good point, but I disagree; I actually adhere to one of two theories - panspermia or ribozymic origins. However, even panspermia does not in fact answer our question of origin.
I believe that life is just an emergent property of the universe - possibly much more common than we may think. There have been some experiments done on ribozymes but I failed to link to any serious articles previously here are some to get you started:
https://www.ncbi.nlm.nih.gov/pubmed/7672511
https://www.nature.com/articles/srep11405
The fact that the Earth was incredibly hot is not up for contention one does have to admit though that if life eventually came to live on Earth these conditions must have changed. I believe that after significant cooling the Earth became apt for the 'creation' of life.
I agree that life could be a integral part of the universe and i think that it could come down to thermodynamics or just entropy.
Since the generating of heat by an elephant would be thermodynamic favorable even with the lower entropy(initialy) life might simply condensate in to existence with the right conditions. Life makes the progress of going from big bang to a cold dark universe faster, so it seems logical that no other explanation is needed.
And since humans make this progress even faster with machines etc we could argue that our existence and all of evolution, could be blamed on the laws on thermodynamics.
Read about it a while ago and i like the fundamental simplicity, and have been reading about the beginning of life, all my life, it even made me chose bio engineering as a career.
I haven't seen any models explaining how the bio molecules needed for RNA was available and how RNA could be its own enzymes and have access to material for next generation RNA. Or how the information in the first RNA made scenes in context to molecular life.
There is still much to look for and the statistics still look bad right :)
Particles in the universe 10^80
Chase that life happens randomly @ earth 10 ^100000
The pre-biotic soup had the necessary building blocks. Why is it that you think that RNA couldn't self replicate?
Lack of RNA nucleotides obviously still no evidence or theory can explain the abundance needed, pools of it for millions of years to suport random self assembly into RNA of usefull composition followed by self replication for million of years with no membrane or safe environment on a very hot earth, hardly possible of carrying life as we know it.
But its moving forward, some even propose pre RNA molecules evolving into RNA with some catalytic effects as temperatures droped etc.
I gladly follow the progress, but i am naturally skeptic to evolution and big bang, it´s being taken for granted by many but we should not forget it is still theories that carries a lot of flaws :)
interesting debate you got going on guys. My research sense has been further triggered. I will look deeply into both sides of the argument and see if I can come up with something more evidence based.
It is an interesting question :) good luck!
The DNA came first and occupies the central portion. It is a precursor to all other biomolecules associated with information transfer, that is RNA and protein. The messages in DNA are first transcribed into RNA and then translated into proteins.
Thanks for reading through
Yeah true that it´s central and a precursor in a scene. But DNA would never self assembly, especially into something of useful information, it could not be stored without a cell membrane and it could not be transcribed or replicated without enzymes.
Its like having code with no computer, it simply WILL NOT compute alone.
Biomolecules of life came first before the evolution of the cell. Perhaps I should do something on the origin of cells itself
yeah try to find the mechanism starting life :)