DNA from nothing

[Tristan]

Hi All,

In a book I read it claims that all observed evolution today (i.e. adaptation) never involves the generation of NEW genetic information. It involves the changing and/or degredation of existing genetic information.

I've asked this question before in a couple of threads but got no reply, so I've decided to start a different thread for it:

Is there any evidence to show that new genetic information can spontaneously be generated from nothing? Is there any observed occurrances of it?

Thanks & God bless,

Tris

 

[Jerry Smith]

Originally posted by Tristan
Hi All,

In a book I read it claims that all observed evolution today (i.e. adaptation) never involves the generation of NEW genetic information. It involves the changing and/or degredation of existing genetic information.

Hi Tris!
The interesting thing about genetic "information" is that any time it is "changed", that change essentially constitutes new "information", in the form of a new nucleotide sequence. Since all there is to genetic "information", then any new nucleotide sequence is new genetic "information".

I've asked this question before in a couple of threads but got no reply, so I've decided to start a different thread for it:

Is there any evidence to show that new genetic information can spontaneously be generated from nothing? Is there any observed occurrances of it?

From nothing? No. From parent DNA, Sure. Polyploidy is observed all the time, and it can do as much as double the genetic information of a cell (even though all it does is make an extra copy of what is already there, more or less... it "makes room" for future mutations that change the genetic information of the organism, so polyploidy increases the information capacity of the organism's genome while leaving the content alone for the most part.

Now usually, new information is "garbage"- that is, it has no effect on how the organism develops. Often it is even harmful to the new organism, so that it doesn't stay in the genome of that species long. But sometimes, it causes changes to the organism that help the organism survive and reproduce in its natural environment. Those changes are more likely to survive through reproduction, and that is one of the most basic ways in which evolution works.

These "beneficial changes" are sometimes observed, but they are rare because they do not happen "frequently" (by the standard of a human's short life-span). A good example of beneficial changes to the genetic information of an organism is bacterial resistance to antibotics. This has been observed rigorously in the lab. There are a few other examples if you are interested.

 

[mac_philo]

That all sounds good to me. We often forget that the information present in dna has a ludicrously simple synatax. Humans are constructed our of different combinations of only four building blocks: A, C, T, G. When you realize that genetic differences are just variations in the assemblage of those four bits, the idea that there is any diffence between 'new' information and 'changed' information loses all force.

This question is asked very frequently, and I think the hidden assumption is that a new phenotype is similar to a new human artifact--a unique creation. Unique phenotypes just come from a unique assemblage of the same old bits.

 

[LouisBooth]

So according to ya'll any mutation in any gene whatsoever implies a new species?

 

[Jerry Smith]

Originally posted by LouisBooth
So according to ya'll any mutation in any gene whatsoever implies a new species?

Louis, are you serious? I don't know about mac_philo, but I was answering Tristan's question about "adding genetic 'information'". The topic of speciation hadn't come up.

 

[mac_philo]

Originally posted by LouisBooth
So according to ya'll any mutation in any gene whatsoever implies a new species?

Of course not. Do you read our posts?

The query was whether or not mutations provide new information. The answer was that new information is just changed information.

A species denotes a set of organisms that can reproduce with each other, but not with any organism outside the set.

How you've jumped from the former topic to the latter is rather opaque to me.

 

[chickenman]

one of the major sources for new information and increasing complexity through modifications to DNA is duplication, whether it be gene duplication or entire chromosomal duplication (polyploidy)

 

[LouisBooth]

*sigh* I was asking for clarification since you made it blantly obviuos you wanted lurkers to be aware of things, plus it was for my clarification. Thanks for understanding

 

[Josephus]

So in short, there is no such thing as increased genetic information within a species over time - all "new" information is just "changed" information?

 

[mac_philo]

Originally posted by LouisBooth
*sigh* I was asking for clarification since you made it blantly obviuos you wanted lurkers to be aware of things, plus it was for my clarification. Thanks for understanding

The distinction was already obvious to anyone with even the barest acquaintance with this subject, and since you pass yourself off as an expert capable of disproving various biological theories, it never occured to me you would need such a clarification.

Also, your sigh is unwarranted. I did *not* make the point about the lurkers, which you just attributed to me. That was a different infidel who doesn't believe in the gospel according to Louis and who will suffer in the lake of fire. We aren't all identical, though there sure are lots of us.

 

[Jerry Smith]

Originally posted by Josephus
So in short, there is no such thing as increased genetic information within a species over time - all "new" information is just "changed" information?

yes and no. Gene duplication and polyploidy increase "information" capacity, while duplicating "information" content. Point mutations, base-line shifts and numerous other mutations to change "information" content (sometimes neutral, sometimes deleterious, sometimes beneficial). If you have gene duplication and other kinds of mutations together, then the result is an increase in the total amount of information (sometimes "useful" or "beneficial" information).

Information, in a genetic sense, is a reduntant term. You might as well refer to it without the simile. You might as well refer to changes in the genetic structure. But since Tristan asked about "information", I tried to give her an answer in those terms. I hope that both you and she can follow the answer: I am assuming you are both familiar with how nucleotide sequences in DNA form the template for proteins and catalysts which regulate an organisms function and development.

 

[mac_philo]

Originally posted by Josephus
So in short, there is no such thing as increased genetic information within a species over time - all "new" information is just "changed" information?

I don't see the correlation you're drawing.

Consider all the paintings in the metropolitan museum of art. Cut them all into square inch pieces. Change the color of a small percentage of the pieces, and reassemble the pieces.

Are these 'new paintings' or merely 'changed paintings'? I'm not sure the distinction is meaningful, and the only reasonable answer (to me) is to say it's both.

Consider a lego replica of Manhattan constructed out of 100,000,000 Lego blocks. Now consider constructing a model of Venice with those same blocks. Is this a 'new' model, or just a 'changed' model?

I don't think we can answer this question without coming up with a sensible difference between the two concepts.

In any case, why would either answer be relevant to whether there is an *increase* in information? This is even less clear to me. What do you mean?

Are you saying that the size of the genome increases? What? Phenotypic differences come through mutations, not through changing the length of the genome. We aren't talking about adding genes or chromosomes.

If by increase you mean size, that's unhelpful. The size of the genome is pretty irrelevant; ours isn't much bigger than a tapeworm's, and ours is quite literally full of garbage sequences.

I think we should discuss what these words mean to you before we try to figure out how they apply to a specific biological phenomenon.

 

[Josephus]

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[Josephus]

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[Josephus]

I'm talking about increasing the number of lego blocks you have to work with over time.

It is near-impossible to increase the amount of genetic material in a DNA strand, and any added material that does manage to mutate into its duplication are usually lost to generations of duplication afterwards, perhaps just as "easily" as it was gained in the first place. It is my determination because of this that mathematically it could even represent a 50/50 chance of survival of a newly added piece of material, and that this whole process of losing it again due to the same errors that created it inthe first place, occurs way before it is even duplicated to usefulness.

Hence, no net increase.

And is it me, or does new genetic material in a DNA sequence usually pose a greater problem for defects later on?

 

[mac_philo]

I think by defect you mean mutation. Mutations occur because the transcription process (the process of duplicating the strand) is not 100% accurate. Mutations don't cause more mutations in this sense. (Though I could be wrong, and perhaps there could be a mutation that would degrade transcription fidelity.)
But as for just phenotypic defects, yes, most mutations are maladaptive, or at least don't increase fitness. A miniscule few do, though, and this is how species adapt.
But again, having more lego blocks to work with.... We have a finite number of genes, and it's clear that we have a vast difference in phenotype, so I don't understand the problem. We know that 'mere differences' create different phenotypes--what is this desire for something 'new'?

Also, I think the 50/50 odd is astronomically off. The transcription process is very, very high fidelity, and mutations are very rare. You seem to be making some teleological assumptions here, like 'evolution was trying to make something new, but look, it could cook up this new gene and then lose it because it mutates back to the way it was before.' Sure, it's mathematically possible that successive mutations would happen in a lineage in just this manner. But I don't see why it's a problem, and it certainly isn't a 50/50 chance. The odds of a transcription error (or of any cause of mutation) are exceedingly great; the odds that the same gene will mutate successively are precisely twice as remote as the odds of the initial mutation occuring. An astronomically remote possibility. But sure, remote possibilities can happen, and over time, with millions of genes and millions of years, it's just bound to happen.

But I still don't understand what having 'more to work with' means. Our genome is huge, yet contains seemingly endless sequences of garbage information. Getting useful changes out of the garbage sequences would seem to give you everything you're looking for here.

EDITED to add: not twice as remote, but rather, the original probability raised to the second power. (i think)

 

[seebs]

Originally posted by Josephus
I'm talking about increasing the number of lego blocks you have to work with over time.

It is near-impossible to increase the amount of genetic material in a DNA strand, and any added material that does manage to mutate into its duplication are usually lost to generations of duplication afterwards, perhaps just as "easily" as it was gained in the first place. It is my determination because of this that mathematically it could even represent a 50/50 chance of survival of a newly added piece of material, and that this whole process of losing it again due to the same errors that created it inthe first place, occurs way before it is even duplicated to usefulness.

Hence, no net increase.

And is it me, or does new genetic material in a DNA sequence usually pose a greater problem for defects later on?

Point of fact: I believe it's well established how you can add length to a genome without necessarily changing anything, and it's been observed widely. And yes, this can increase the chance of defects... but every so often, a "defect" turns out to work really well.

I have heard reasonable arguments suggesting that the ability of mammals to bear live young is based on some DNA hijacked from a virus millions of years ago. (There's a need to somehow defeat the body's immune system.)

 

[seebs]

Originally posted by mac_philo

EDITED to add: not twice as remote, but rather, the original probability raised to the second power. (i think)

That's a good approximation. Some mutations may change the chance of a future mutation, in which case, it's different.

I think a lot of the "new information" debate is based on lack of information theory. I would suggest that anyone who wants to discuss "new information" find out about how compression works, and why a change in what some of the pieces of data in a stream of a fixed length *are* can change the *EFFECTIVE* length of the stream of data - the total information encoded by it.

To make a long story short, if you have two streams of bits:

0000000000000000

and

0110010101010001

The second has "more information", even though every individual difference between them is simply a "change", not an "addition"... but the complexity is different, so we have to say the second stream contains more data.

This isn't necessarily any easier to believe without learning the math than any other belief, but it has the arguable advantage that you *CAN* learn the math, at which point, it's pretty compelling.

 

[Jerry Smith]

not twice as remote, but rather, the original probability raised to the second power. (i think)

The probability of any mutation occurring is incalculably higher than the probability of any one specific mutation occurring. When a mutation does occur, then the probability that the specific reverse mutation will usually be roughly the same as the probability of the first specific mutation (which is a very low probability).
Nevertheless, if the first mutation is selected for and the "reverse" does eventually happen, it is not likely that the "re-instated" original sequence will ever come to dominate the population, and will not likely be preserved through very many generations.

Josephus,

It is near-impossible to increase the amount of genetic material in a DNA strand,

I'm sorry, the truth is that gene and chromosome duplication frequently increase the amount of genetic material in an organism's DNA. This happens more often with some organisms than others, but it is a universal phenomenon.

 

[Josephus]

Our genome is huge, yet contains seemingly endless sequences of garbage information.

Would it seem more plausible that these sequences are the result of genetic mutation which made them lose their original function, or the ADDITION of more sequences? Which is more probable: the mutation of a sequence going bad, or the ADDITION of a new sequence?

The answer (which is the former) ultimately, is my premise to the idea that there is a net information loss over time, hence, deevolution.