[HN Gopher] Origin of life theory involving RNA-protein hybrid g...
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Origin of life theory involving RNA-protein hybrid gets new support
Author : gmays
Score : 42 points
Date : 2022-05-13 18:34 UTC (4 hours ago)
(HTM) web link (www.nature.com)
(TXT) w3m dump (www.nature.com)
| oneoff786 wrote:
| It seems difficult to imagine DNA forming without first single
| strand RNA no?
| ralusek wrote:
| Just because a hypothesis seems likely doesn't mean it doesn't
| require evidence.
| oneoff786 wrote:
| The article suggests the dna hypothesis was the front runner
| for a while though
| creatonez wrote:
| No? The article is talking about RNA World hypothesis vs.
| RNA-Protein World hypothesis. The RNA world hypothesis has
| been accepted widely for a long time.
|
| Before membraneless RNA viroids were discovered, some
| abiogenesis researchers may have thought that DNA is
| fundamentally required for self-replication, so whatever
| first occurred must have had it. But this is simply a lack
| of imagination on what RNA can do.
| jononomo wrote:
| The origin of life is in fact the ONLY interesting scientific
| question because without life no other question arises.
|
| Also, the fact that there are individual proteins that must be
| found in a search space that is on the order of 10^70, while only
| 10^50 living organisms have ever existed on Earth puts to rest
| the "random mutation" theory of how life evolved.
|
| There was a time when mathematicians in the academy openly mocked
| the biologists who bought into the "random mutation plus natural
| selection" creation myth, but sadly those days are over because
| raising the obvious questions now puts an academic career at
| risk.
|
| It is commonly assumed that it is impossible to definitively
| prove the existence of God, but in fact the existence of life is
| a definitive proof of the existence of God, given what we now
| understand about molecular biology.
|
| Here is an interesting book: The Stairway To Life: An Origin-Of-
| Life Reality Check
| https://www.amazon.com/dp/1734183705/ref=cm_sw_r_cp_api_i_DA...
|
| Frankly it is game-over for atheism from a strictly empirical
| perspective.
| andrewflnr wrote:
| I used to think this, but the work of Jeremy England (IIRC) has
| convinced me that the emergence of life is thermodynamically
| favored. FWIW I'm not down voting.
| monkeycantype wrote:
| I love the RNA world hypothesis, I love the idea that DNA is an
| iteration on RNA optimised for stable data storage, that proteins
| are and iteration on RNA optimised to be better enzymes and
| structures and that mediating between the two we still have to
| transcribe data to the legacy RNA data format, and use the legacy
| RNA enzyme ribosomes to translate this through to amino acid
| sequences.
|
| The idea the RNA metabolisms might have evolved in small cavities
| in hydrothermal vents also makes it easy to imagine communities
| of cooperating molecules in an enclosed area needing to defend
| themselves from free-loading virus molecules, setting up the
| ongoing conflict between cells and viruses right from the
| beginning, and also a dynamic in which viruses are both
| destructive and an important source of novelty
| ncmncm wrote:
| Imagine the seas a thick soup of iron complexes and RNA folded
| into quadrillions of nightmare shapes, a vanishing few of them
| busy replicating whatever they bumped into. One day, two of
| them bumped into one another. In the blink of a geologic eye,
| the seas were brimming with a descendant of whichever of them
| was faster.
|
| Somewhere, a membrane happened. I don't think anywhere in
| nature today do we find a membrane created entirely from
| scratch. Everywhere we find a membrane, it grew from and split
| off of an existing membrane. It may be that we should think of
| ourselves as fancy membranes, and DNA, RNA, and protein are
| just clever ways to make more membrane.
| convolvatron wrote:
| my hazy memory is that it is/was assumed that the cell wall
| arose pretty naturally from an asymmetric protein that was
| hydrophilic on one end and hydrophobic on the other.
| achillesheels wrote:
| I love the idea that this can be modeled using Signals and
| Systems Theory, e.g. Fourier Analysis of the digital signaling
| of protein sequencing
| divbzero wrote:
| Could there be an unknown class X of biomolecules that was
| involved in the origin of life but was later outcompeted by the
| DNA + RNA + protein combo that dominates today? This class X
| could have been less efficient at replication but kinetically
| easier to form from the primordial broth.
| stainablesteel wrote:
| it would likely be something of a hybrid nature or an extremely
| similar precursor, nothing drastically different
| exyi wrote:
| For sure it's possible, but evolution rarely gets completely
| rid of something (as far as we know). My favorite support for
| RNA-world (and similar) hypothesis is that RNA molecules are
| used as enzymes in some processes (ribosome - translation),
| even though RNA is a pretty bad catalyst. If the evolution
| could choose, it would most likely use a protein, but the cost
| of switching to "new tech" is too high.
| ncmncm wrote:
| The environment at the time life evolved was very, very
| different from today.
|
| In particular, free oxygen was practically non-existent.
| Metals, particularly iron, and metal complexes were dissolved
| in the water at high concentration. Processes that spawned the
| first life had to be compatible with all of that, and may well
| have depended on many details of it, most of which we can
| barely imagine. The ancestors of everything alive today
| survived the arrival of free oxygen a billion or two years
| later, with the loss of most dissolved metals, leaving no trace
| of the overwhelming majority that failed to adapt to that.
|
| Conditions today, even without competition from existing life,
| might be wholly unsuitable for biogenesis.
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