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Author Topic:   Deep Homology and Front-loading
Dr Adequate
Member (Idle past 285 days)
Posts: 16112
Joined: 07-20-2006


Message 168 of 172 (667505)
07-08-2012 1:41 PM
Reply to: Message 167 by Genomicus
07-08-2012 9:49 AM


You're ignoring the key issue: that, under the non-telic model, LUCA could have been a simple prokaryote that did not require eukaryotic proteins. Is it not true, that under the current theory, the LUCA could easily have been only a simple prokaryote?

Yes, that's perfectly true, but it's not what you said. What you said was: "Essentially then, the non-telic model predicts that the LUCA did not have a minimal genome." So I pointed out that it does not in fact make that prediction.

No. As I stated in the OP, front-loading requires that the genome of the LUCA be more than a minimal genome. Indeed, some evidence indicates it was minimal. But the idea that the LUCA's genome was minimal is not compatible with front-loading, and thus we can predict that key eukaryotic proteins will share deep homology with prokaryotic proteins that are functional but unnecessary for a minimal genome, which in turn would mean that the LUCA's genome was not minimal.

I must have misunderstood the point I was replying to, then.

I still can't see what you were getting at here.

On the one hand, you say that: "the idea that the LUCA's genome was minimal is not compatible with front-loading" --- i.e. FLE would predict a non-minimal genome.

OTOH, you say that: "the non-telic model predicts that the LUCA did not have a minimal genome".

But weren't you meant to be looking for a prediction that FLE made and Darwinism didn't? You seem to have asserted in separate posts that both of them predict the same thing.


This message is a reply to:
 Message 167 by Genomicus, posted 07-08-2012 9:49 AM Genomicus has replied

Replies to this message:
 Message 169 by Genomicus, posted 07-09-2012 4:42 PM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 285 days)
Posts: 16112
Joined: 07-20-2006


Message 171 of 172 (667588)
07-10-2012 12:25 AM
Reply to: Message 169 by Genomicus
07-09-2012 4:42 PM


You (Dr Adequate), along with Catholic Scientist, seem to be in agreement with this (i.e., that it is not unreasonable in the non-telic model for the LUCA to have only a minimal genome) ...

Yes. If I had to put money on it, I think I'd lean towards it being non-minimal. It is, after all, the last universal common ancestor; but this is merely a hunch, and I wouldn't be at all shocked to learn that it was minimal after all.

I'd say that the scientific literature, for the most part, supports the former contention: namely, that it is not unreasonable for the LUCA to have only a minimal genome under the current theory.

Do bear in mind that when they say that, that's not a prediction of the theory, it's an interpretation of the observations in light of the theory. Now since your version of FLE maintains that evolution was Darwinian after LUCA, it follows that if they're right that this is the Darwinian interpretation, it must also by the same token be the interpretation of (your version of) FLE.

To put it another way, if it is consistent with modern observations and with Darwinism to say that LUCA could have been minimal, it is also consistent with your FLE to say that it could have been minimal. So for the sake of your argument, you should be hoping that the scientists who say this are wrong, whereas you seem to be hoping that they're right.

Edited by Dr Adequate, : No reason given.


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Dr Adequate
Member (Idle past 285 days)
Posts: 16112
Joined: 07-20-2006


Message 172 of 172 (667609)
07-10-2012 12:59 PM
Reply to: Message 171 by Dr Adequate
07-10-2012 12:25 AM


To clarify my point.

When scientists speculate about what LUCA was like, they are not doing so by saying: "Abiogenesis is true, and Darwinian processes reigned between abiogenesis and LUCA, therefore we can deduce such-and-such a thing about LUCA".

Rather, they are saying: "The observations we make of modern organisms are true, and Darwinian processes reigned between LUCA and modern organisms, therefore we can deduce such-and-such a thing about LUCA".

And you agree with their premises.

So if you're going to say that FLE predicts a priori a non-minimal genome for LUCA, then what you would want them to say is that their interpretation is that LUCA had a non-minimal genome.

But I think you're wrong about what FLE predicts. I have no difficulty conceiving of aliens (for example) seeding our planet with organisms with a minimal genome, which then evolved in a Darwinian way to produce the diversity of life we see today. I have no problem with this because I also have no problem with believing that LUCA had a minimal genome, was not seeded by aliens, and produced the same results by the same mechanisms.

The question of whether LUCA was or was not minimal can be decided, if at all (which I doubt very much) not a priori from the competing hypotheses of Darwinism and FLE, but a posteriori from the data about modern organisms that we now have in front of us. Which totally screws your argument.


This message is a reply to:
 Message 171 by Dr Adequate, posted 07-10-2012 12:25 AM Dr Adequate has taken no action

  
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