Feral Hogs

[m_the0ry]

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It's like there are dormant dna instructions ready to take effect under the right enviornmental conditions.

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Sure, we have mapped the genome, but we still have almost no idea how genes work. 'Junk' DNA that doesn't seem to do anything is everywhere. Yet DNA directly affects protein synthesis. With terabytes of information - each bit possibly having immense (or zero) significance - a DNA sequence is really just a tangible representation of what uniquely identifies an organism. Evolution is a recursive process occurring over huge times scales and an innumerable range of environmental variables. Ice ages are severe climate changes and they only happen over a few years.

Is it really unreasonable imagine that an organism can evolve to evolve?

[Metric]

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Sure, we have mapped the genome, but we still have almost no idea how genes work. 'Junk' DNA that doesn't seem to do anything is everywhere. Yet DNA directly affects protein synthesis. With terabytes of information - each bit possibly having immense (or zero) significance - a DNA sequence is really just a tangible representation of what uniquely identifies an organism.

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I'm curious how this concept is handled by geneticists -- do they explicitly use the mathematical tools of classical information theory to discuss these concepts and gain new insights? If not, is it simply that there's no working theory (starting from certain postulates) to put the mathematics to work?

[PairTheBoard]

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I think something like what you are talking about is the current understanding. Not only do we evolve, but we evolve evolvability.

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If that's the current understanding it hasn't percolated down to the Popular Level that includes me yet. I'd be happy to see articles explaining that as the accepted view in the field. I'd especially like to see what they think the mechanisms are for it.

PairTheBoard

[Alex-db]

Perfect replicators couldn't evolve. Completely random mutators would be too unstable. The predominant replicators will have evolved towards an optimum ability to evolve: not too perfect, not too imperfect.

So when the environment changes, the ones with the most optimum ability to change again will become the most frequent.

[Rduke55]

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A recent development in theory which was laughed at when first suggested.

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Are you talking about Lamarckism? Because if so, then you're mistaken because it was very much in vogue for a long time in evolutionary theory. Even Darwin was a Lamarckist.


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I wonder how the intelligence of the species might get involved. There seems to me to be a feedback between stress and the experience of it by intelligence.


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Not sure what you mean here.

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I know this is theoretical heresy for evolution, but if epigenetics can direct physical changes, why couldn't it direct alterations to the dna itself?

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The mechanism would be orders of magnitude more complex.


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Wouldn't it be an evolutionary advantage for a species under intense environmental stress to direct rapid alterations in its dna? Thus giving it a chance to produce a lot of radically "new models" in the next generation - one of which might be able to survive in an environment so stressful it is likely to be forcing the original form of the species into extinction. Wouldn't such a mechanism have evolutionary advantages?


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What would be the advantage over something like the mechanisms of epigenetic change described in the article? That gives you a lot more flexibility to change with your pressures.
Also, I'd have to think that the probability for things to go wrong would be much, much greater using a mechanism you are proposing than the one we are talking about.

[Rduke55]

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I don't see the problem. The trait I'm thinking of could be relatively simple and applicable to almost any dna structures beyond the dna that directs it - Call that the Safe dna. Like, when under intense pressure the epigenetic mechanisms do major alterations of the UnSafe dna, like cutting off a piece, or adding a piece, or something like that. It takes what it has to work with and does some rearangements.

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The problem is that I'd imagine this would result in a lot of nonfunctional and/or deleterious genes. Most of the time cutting off a piece or adding a piece has really bad repurcussions.

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I assume they mean the effect lasts for several generations even after the predators have been removed.

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It does.

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heretical

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You keep using this word. Heretical to whom?

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I really doubt we know everything about how dna gets altered.

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I agree.

[Rduke55]

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'Junk' DNA that doesn't seem to do anything

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I really wish this idea would go away.

[Rduke55]

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I'm curious how this concept is handled by geneticists -- do they explicitly use the mathematical tools of classical information theory to discuss these concepts and gain new insights?

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I think some may use it as a useful analogy in some cases but it's not used by geneticists all that much, at least the kind of information theory and extent you are talking about. I would guess that things like how evolution progresses by "tinkering", and problems in what genetic communication is are what cause problems with using IT for this.

[m_the0ry]

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'Junk' DNA that doesn't seem to do anything

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I really wish this idea would go away.

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Why would it? We have always been able to watch RNA transcription and protein synthesis. Inexplicably there are non-coded sequences that are never transcribed and never have any affect on the organism.

The point of bringing up the 'junk' DNA was a way to demonstrate that we understand very little about the higher level nature of DNA with respect to it being a product of evolution. We can't definitively say, "if this piece of DNA were active the organism would look different in this way". But junk DNA is definitely a real thing. The information may be dormant for 1 generation or 50 or 5000, or come alive from environmental changes, or never be active.

[Rduke55]

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Inexplicably there are non-coded sequences that are never transcribed and never have any affect on the organism.

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This is really, really wrong. While I'm sure that a lot of it is not used noncoding DNA has enormous effects on the organism. A lot of our genes (as in coding region) range from pretty similar to exactly the same as other organisms - the difference is how those genes are expressed. Many people that work on these kinds of things think that kind of thing makes up the main differences between different related organisms. You need noncoding DNA for genes to get turned on, off, when, where, etc.
In fact I'd say a huge chunk, if not most, of the changes of our brain between us and say, chimps, have to do with differences in developmental timing during the formation of the nervous system. Are there coding differences that play a big role? Of course, but for some reason people really don't know about the gigundous role expression differences, which are governed by noncoding regions that are not transcribed or translated into proteins, play.

I've posted before on the prairie vs. montane vole differences in mating systems that are based on different expression of the same gene. That's relevant here.