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The RNA World Hypothesis

ncbi.nlm.nih.gov

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Re: The RNA World Hypothesis

#31

Post by [deleted] »

adrian_b wrote: post #17
Sharlin wrote: post #14

Earlier quoted context omitted.

> So there must have already existed an equivalent of a bacteria, with metabolism using energy from the environment (i.e. dihydrogen with carbon dioxide and ionic gradients), which was already able to make ATP, which would have been needed to synthesize the polymers made by condensation, e.g. peptides. The apparition of the first RNA virus was an initially undesirable side-effect of using ATP to perform polymer conde…

Yes, that is exactly that what I have said. While there was replicating RNA before any DNA and before any proteins made by translation from RNA, metabolism must have existed before any RNA and catalysis must have been done with peptides produced by other ways than translation from RNA (today there still are such non-ribosomal peptides). Speaking about a RNA world is correct only in this sense, because RNA could not h…

[deleted]

Re: The RNA World Hypothesis

#32

Post by TchoBeer »

adrian_b wrote: post #17
Sharlin wrote: post #14

Earlier quoted context omitted.

> So there must have already existed an equivalent of a bacteria, with metabolism using energy from the environment (i.e. dihydrogen with carbon dioxide and ionic gradients), which was already able to make ATP, which would have been needed to synthesize the polymers made by condensation, e.g. peptides. The apparition of the first RNA virus was an initially undesirable side-effect of using ATP to perform polymer conde…

Yes, that is exactly that what I have said. While there was replicating RNA before any DNA and before any proteins made by translation from RNA, metabolism must have existed before any RNA and catalysis must have been done with peptides produced by other ways than translation from RNA (today there still are such non-ribosomal peptides). Speaking about a RNA world is correct only in this sense, because RNA could not h…

>such a mechanism could not appear in any environment where ATP and the other nucleotides did not already exist.

What evidence is there that this is true

Re: The RNA World Hypothesis

#33

Post by Mezzie »

kubanczyk wrote: post #22
COGlory wrote: post #2

If anyone is interested in further reading on this topic, or on evolution/origin of life in general, I highly recommend "The Logic of Chance" by Eugene Koonin. The book pieces together the latest knowledge from all the major fields of biology (genetics/bioinformatics, structural/physics, etc), math, physics, and philosophy in a way I've never seen done before. It interrogates virtually every hypothesis of the origin…

I've looked on Google Books' preview and it reads quite smoothly. I was surprised that Google's price is so much lower than Amazon's though? Less than a half? (Might be locale-dependent, I'm in Poland). It has been long since I bought anything on Google, but I assume it can still be converted to a DRM-free epub like described here?: https://www.reddit.com/r/kindle/comments/3menci/i_prefer_my_... Where's the catch?

Converting the book files is dead easy; Calibre can make pretty much any format you want. I'm visually-impaired so I prefer eBooks, but screw DRM. If I buy a book, it's MY book. Screw Amazon too.

Re: The RNA World Hypothesis

#34

Post by ramraj07 »

usrbinbash wrote: post #24
ramraj07 wrote: post #16

I have no doubt that our life originally evolved from an RNA world. I’m just not convinced the world is earth. This shit could not have happened so fast (few tens or hundreds of million years?) the moment it became conducive on earth. It must have flown in as archea from elsewhere! Also anyone who’s worked in a lab trying to keep some Lb plates sterile would immediately see how difficult it would be to keep an earth…

>This shit could not have happened so fast (few tens or hundreds of million years?) It didn't happen that fast. The earliest direct evidence, (as in: fossils) for life on earth are 3.465 BILLION years old. https://en.wikipedia.org/wiki/Earliest_known_life_forms >Also anyone who’s worked in a lab trying to keep some Lb plates sterile would immediately see how difficult it would be to keep an earth sized Lb plate steri…

Read your own ref. Optimistic estimates put the first appearance of life on earth as soon as 50 mill years after oceans formed.

The Petri dish analogy was only supposed to be tounge in cheek but if you want to be pedantic then consider that the medium between the source and destination is a frozen vacuum which means you have billions of years for transmission and spreading.

Re: The RNA World Hypothesis

#35

Post by usrbinbash »

ramraj07 wrote: post #34
usrbinbash wrote: post #24

Earlier quoted context omitted.

>This shit could not have happened so fast (few tens or hundreds of million years?) It didn't happen that fast. The earliest direct evidence, (as in: fossils) for life on earth are 3.465 BILLION years old. https://en.wikipedia.org/wiki/Earliest_known_life_forms >Also anyone who’s worked in a lab trying to keep some Lb plates sterile would immediately see how difficult it would be to keep an earth sized Lb plate steri…

Read your own ref. Optimistic estimates put the first appearance of life on earth as soon as 50 mill years after oceans formed. The Petri dish analogy was only supposed to be tounge in cheek but if you want to be pedantic then consider that the medium between the source and destination is a frozen vacuum which means you have billions of years for transmission and spreading.

Yes, and these oceans formed 4.5 billion years ago, aka. much longer than "few tens or hundreds of million years"

> then consider that the medium between the source and destination is a frozen vacuum which means you have billions of years for transmission and spreading.

And by what means does that spreading take place? Spreading implies a medium through which to spread, which doesn't exist in interstellar space.

So that leaves moving over that distance on a fragment of a shattered planetoid for example. The fastest known asteroid, 2021-PH27 clocks at around 106 km/sec. Meaning, it would require about 2800y to make it's journey (remember, this is still alpha centauri I'm talking about, which by all accounts has no planets in the habitable zone).

2800 years at top speed thorugh the vacuum of space, unshielded from the denaturing effects of cosmic radiation. And at the end of that travel, if it isn't swallowed up by the gravitational forces of the sun or our 2 gas giants, an impact event comparable to a large thermonuclear device going off.

Sorry, but compared to that, sponeneous abiogenesis sounds a lot more plausible to me.

Re: The RNA World Hypothesis

#36

Post by [deleted] »

adrian_b wrote: post #13
COGlory wrote: post #2

If anyone is interested in further reading on this topic, or on evolution/origin of life in general, I highly recommend "The Logic of Chance" by Eugene Koonin. The book pieces together the latest knowledge from all the major fields of biology (genetics/bioinformatics, structural/physics, etc), math, physics, and philosophy in a way I've never seen done before. It interrogates virtually every hypothesis of the origin…

About virology, there is no doubt that the first RNA molecule was a virus. All the popular presentations about the "RNA world" are either incomplete and/or logically inconsistent. There certainly was a RNA world, in the sense of a world where there was no DNA, but only RNA. However, there must have existed 2 stages of the RNA world, the later stage, when protein synthesis based on translation from RNA existed, like t…

[deleted]

Re: The RNA World Hypothesis

#37

Post by [deleted] »

adrian_b wrote: post #17
Sharlin wrote: post #14

Earlier quoted context omitted.

> So there must have already existed an equivalent of a bacteria, with metabolism using energy from the environment (i.e. dihydrogen with carbon dioxide and ionic gradients), which was already able to make ATP, which would have been needed to synthesize the polymers made by condensation, e.g. peptides. The apparition of the first RNA virus was an initially undesirable side-effect of using ATP to perform polymer conde…

Yes, that is exactly that what I have said. While there was replicating RNA before any DNA and before any proteins made by translation from RNA, metabolism must have existed before any RNA and catalysis must have been done with peptides produced by other ways than translation from RNA (today there still are such non-ribosomal peptides). Speaking about a RNA world is correct only in this sense, because RNA could not h…

[deleted]

Re: The RNA World Hypothesis

#38

Post by [deleted] »

adrian_b wrote: post #28
usrbinbash wrote: post #27

Earlier quoted context omitted.

>and also an earlier stage, when only RNA replication existed, but RNA did not perform any useful function for its host living being, but it was only a virus that was replicated using energy and molecular components from its host. And in this stage, where there is no DNA, what molecule carried the genetic information of these host organisms? >Because any memory molecule, like RNA, needs an already existing living bei…

As I have already said, there is no need for genetic information in a living being able to grow and reproduce. The difference between a living being with genetic information and a living being without genetic information is the same as between a processor with micro-programmed control and a processor with hard-wired control. In a processor with micro-programmed control, it is easy to add new instructions or to replac…

[deleted]

Re: The RNA World Hypothesis

#39

Post by [deleted] »

adrian_b wrote: post #17
Sharlin wrote: post #14

Earlier quoted context omitted.

> So there must have already existed an equivalent of a bacteria, with metabolism using energy from the environment (i.e. dihydrogen with carbon dioxide and ionic gradients), which was already able to make ATP, which would have been needed to synthesize the polymers made by condensation, e.g. peptides. The apparition of the first RNA virus was an initially undesirable side-effect of using ATP to perform polymer conde…

Yes, that is exactly that what I have said. While there was replicating RNA before any DNA and before any proteins made by translation from RNA, metabolism must have existed before any RNA and catalysis must have been done with peptides produced by other ways than translation from RNA (today there still are such non-ribosomal peptides). Speaking about a RNA world is correct only in this sense, because RNA could not h…

[deleted]

Re: The RNA World Hypothesis

#40

Post by [deleted] »

TchoBeer wrote: post #32
adrian_b wrote: post #17

Earlier quoted context omitted.

Yes, that is exactly that what I have said. While there was replicating RNA before any DNA and before any proteins made by translation from RNA, metabolism must have existed before any RNA and catalysis must have been done with peptides produced by other ways than translation from RNA (today there still are such non-ribosomal peptides). Speaking about a RNA world is correct only in this sense, because RNA could not h…

>such a mechanism could not appear in any environment where ATP and the other nucleotides did not already exist. What evidence is there that this is true

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