[HN Gopher] New study sheds light on how amino acids "evolved"
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New study sheds light on how amino acids "evolved"
Author : Amorymeltzer
Score : 59 points
Date : 2023-04-10 15:29 UTC (7 hours ago)
(HTM) web link (www.salon.com)
(TXT) w3m dump (www.salon.com)
| galaxytachyon wrote:
| Ah the ages old debate about which was the beginning of it all:
| DNA, RNA, or protein.
|
| My favorite superhero fight, or the very first "my origin of life
| can beat your origin of life" discussion. How fun.
| singeezie wrote:
| Man I been always so fascinated by the Miller-Urey experiment.
| Ever since I learned about it on YouTube over a decade ago, I
| went on a PBS binge on evolution and science shows even though I
| have no formal education only high school. Anyways I found this
| article fascinating.
|
| It discusses the mystery of how life emerged on Earth, and how
| scientists have some theories about how complex cellular life was
| generated around 3.7 billion years ago. Scientists believe that
| amino acids existed in great abundance in the Earth's early years
| and contributed to the creation of the first cell. Experiments,
| such as my favorite lol "Miller-Urey Experiment", simulate the
| conditions of Earth's early atmosphere and have produced organic
| compounds such as amino acids. Proteins are the building blocks
| of all living organisms, and understanding how they formed is
| crucial to understanding how life started. Although hundreds of
| different amino acids may have been present on the early Earth,
| all living things rely on only about 20 of these compounds. It's
| Science man...:)
| phkahler wrote:
| So how did they replicate, and what was the selection process?
| galaxytachyon wrote:
| They stitched 25 random amino acids together and then assess
| the resulting polymer for solubility and foldability.
| Solubility requirement is self explanatory, can't have life
| that is insoluble in water. Foldability is basically how likely
| for these polymers to entangle and collapse on itself. This is
| critical because protein folding depends on this process to
| generate highly compact and dense atomic machineries.
|
| They find out stuff that are too soluble can't fold well
| because they prefer water over other amino acid. And that seems
| to exert a selection pressure, ending up with a specific set of
| amino acids that life depends on.
| yyyk wrote:
| >Solubility requirement is self explanatory, can't have life
| that is insoluble in water. Foldability... is critical
| because protein folding depends on this process to generate
| highly compact and dense atomic machineries.
|
| That's a teleological fallacy. Evolution doesn't have a
| destination, therefore you can't assume the evolution
| criteria from the end result only. Imagine looking at all of
| life, adding a 'resulting in human life' criteria and
| therefore completely failing to understand the evolution of
| avians.
|
| If the authors want to argue amino acids 'evolved', they need
| criteria that make sense for amino acids in early Earth
| environment and not assume the result.
| galaxytachyon wrote:
| Not sure what part are you arguing although I get the
| general gist. Still, to make sure I don't misinterpret you,
| can you expand a bit on which part of those requirements
| are teleological fallacy?
|
| The context is for life on earth. All life on earth depends
| on proteins that are (mostly) soluble in water and almost
| all protein requires folding to be functional. It is a
| valid hypothesis to say solubility and foldability are
| necessary criteria. Then they tested it and found based on
| these criteria, the current set of amino acids is favored
| over other sets. Look like good science to me.
| yyyk wrote:
| >It is a valid hypothesis to say solubility and
| foldability are necessary criteria.
|
| Necessary criteria for _life_ , yes. Is it neccesary for
| _evolution_? The article 's argument is that amino acids
| 'evolved'. Evolution needs a selection mechanism, and the
| article does not explain why evolution would favour
| solubility and foldability, so the article* doesn't come
| close to proving evolution happened much less explaining
| its details. Perhaps some other unexplained chemical
| process favoured these acids, or it was an accident.
|
| It's like looking at current status of biosphere, and
| concluding that life optimizes for insectoids because
| insects have the largest biomass. It's just an argument
| that assumes the result.
|
| * Perhaps the article is bad reporting and the reported
| study had an actual argument for this.
| galaxytachyon wrote:
| I see, the actual scientific paper is always a much
| better source for this stuff than a popsci article.
|
| The term "evolution" was used very loosely in the salon
| article. By your standard it would be more appropriate to
| call the process "selection". The amino acids never
| changes or evolved to become anything different, just
| that some were chosen to become the building blocks of
| life while others were ignored. The reasons for this
| selection were likely the two criteria mentioned above
| and that was backed up by the main study.
|
| You will notice I never used "evolution" to describe the
| process in my posts. I skipped the salon article entirely
| and only used the link they provided to read the real
| study so I didn't notice what they said in the salon
| page. Anyway, it is just some semantic stuff.
| anonymouskimmer wrote:
| I wonder how this selection process varied as proteins
| started mixing, or even bonding, with lipids and sugars.
| Probably not that much, though those processes may have
| allowed the gradual inclusion of the other amino acids.
| pneumonic wrote:
| Selection is what the article describes (solubility and
| structure). They don't claim that they reproduced; they're just
| talking about amino acids that come about by non-reproductive
| chemical processes.
| jonnycat wrote:
| Forgive the plug, but I just wrote up a post[1] on simulating
| Hypercycles, which are a model showing how self-replication
| behaviors can emerge through the interactions of simple
| molecules. Not to say that they are _the_ mechanism, but are an
| interesting model for exploring emergent behaviors and the
| conditions under which self-replicating systems can arise.
|
| [1] https://blog.devgenius.io/origins-of-life-building-a-
| hypercy...
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