Feral Hogs
 

I'm watching a National Geographic show about Hogs. They say that the soft haired pink, short snouted, relatively well behaved domesticated farm pigs without tusks revert suprisingly quickly to coarse long haired dark, long snouted, viscious feral hogs with tusks when they escape into the wild. This happens in just a generation or two. My impression from the show is that it doesn't require breeding with other wild feral hogs, although that would explain it better when that's what happens. Is this possible, that with no change to the blood line, domesticated hogs undergo such sudden physical transformation when released into the wild? Their hair grows long, dark and coarse? Their snouts grow long? They suddenly start growing tusks? How could this be explained?

I also saw an interesting show about the dogification of foxes. The theory was that dogs evolved from wolves by being less easily scared. Thereby having an advantage when approaching human trash dumps. To support the theory they pointed to an experiment done with Foxes where they selectively bred foxes that were less easily scared by humans. The amazing thing is, the dogified foxes did not just change in disposition. They underwent physical changes very similiar to the physical differences between wolves and dogs. Their fur became softer and multicolored, along with other notable physical changes.

These are the kinds of things that make me suspect that there is more going on with evolution than we've put our fingers on so far. It's like there are dormant dna instructions ready to take effect under the right enviornmental conditions. With the domesticated Pigs to Feral Hogs example it appears these instructions don't even need selective breeding. They appear to be triggered by the environment alone.

PairTheBoard

Re: Feral Hogs
 

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These are the kinds of things that make me suspect that there is more going on with evolution than we've put our fingers on so far.

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Great post, and I agree. Three billion years of evolution has left life with some surprises up its sleeve.

Re: Feral Hogs
 

[ QUOTE ]
I'm watching a National Geographic show about Hogs. They say that the soft haired pink, short snouted, relatively well behaved domesticated farm pigs without tusks revert suprisingly quickly to coarse long haired dark, long snouted, viscious feral hogs with tusks when they escape into the wild. This happens in just a generation or two. My impression from the show is that it doesn't require breeding with other wild feral hogs, although that would explain it better when that's what happens. Is this possible, that with no change to the blood line, domesticated hogs undergo such sudden physical transformation when released into the wild? Their hair grows long, dark and coarse? Their snouts grow long? They suddenly start growing tusks? How could this be explained?

I also saw an interesting show about the dogification of foxes. The theory was that dogs evolved from wolves by being less easily scared. Thereby having an advantage when approaching human trash dumps. To support the theory they pointed to an experiment done with Foxes where they selectively bred foxes that were less easily scared by humans. The amazing thing is, the dogified foxes did not just change in disposition. They underwent physical changes very similiar to the physical differences between wolves and dogs. Their fur became softer and multicolored, along with other notable physical changes.

These are the kinds of things that make me suspect that there is more going on with evolution than we've put our fingers on so far. It's like there are dormant dna instructions ready to take effect under the right enviornmental conditions. With the domesticated Pigs to Feral Hogs example it appears these instructions don't even need selective breeding. They appear to be triggered by the environment alone.

PairTheBoard

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Interesting story. Definitely don't know the answer in this case...want me to try to imagine one? I think I probably could, just to dismiss the "ZOMG this is unpossible!" argument, but it would be just wild conjecture. Either way, pretty cool stuff, agree with Phil's post.

Re: Feral Hogs
 

Dogs' great evolutionary step was befriending humans. Pretty f-ing sneaky of them. My dog sleeps in my bed all day while I'm at work. Then she sleeps on the floor all night when I'm at home.

Re: Feral Hogs
 

I'd guess if it isn't explained by other, short term factors it could be explained by epigenetic changes. It's not changes in the code, it changes of what, how much, and when genes get expressed. There was an article in Discover or Scientific American within the last 6 months about this. Very rapid changes based on the environment.

Edit: Found the article linky

Something like the water fleas maybe?

Re: Feral Hogs
 

[ QUOTE ]
I'd guess if it isn't explained by other, short term, factors it could be explained by epigenetic changes. It's not changes in the code, it changes of what, how much, and when genes get expressed. There was an article in Discover or Scientific American within the last 6 months about this. Very rapid changes based on the environment.

Edit: Found the article linky

Something like the water fleas maybe?

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Yeah, I was going to guess something along those lines.

Re: Feral Hogs
 

So it's called epigenetics. A recent development in theory which was laughed at when first suggested. I see them talking about "stress" being a factor triggering epigenetic changes. 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.

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? 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?

PairTheBoard

Re: Feral Hogs
 

[ QUOTE ]
So it's called epigenetics. A recent development in theory which was laughed at when first suggested. I see them talking about "stress" being a factor triggering epigenetic changes. 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.

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? 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?

PairTheBoard

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It would have to be heritable. I am reminded of a story from Godel, Escher and Bach, where one of the characters was trying to play any possible record, and the other was trying to design records that, when played, destroyed the recordplayer. He thought of the tactic of designing a recordplayer that would scan the record, find out what type of player it would destroy, and then reassemble itself into some other kind and play the record. You have to have some way of programming the organism to reorganize its DNA while allowing for the DNA that does this programming to be impervious to change. Thus, THAT DNA is now vulnerable since it cannot adapt. Remember, eventually, EVERYTHING is a genetic, not epigenetic, response.

Re: Feral Hogs
 

[ QUOTE ]
[ QUOTE ]
So it's called epigenetics. A recent development in theory which was laughed at when first suggested. I see them talking about "stress" being a factor triggering epigenetic changes. 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.

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? 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?

PairTheBoard

[/ QUOTE ]

It would have to be heritable. I am reminded of a story from Godel, Escher and Bach, where one of the characters was trying to play any possible record, and the other was trying to design records that, when played, destroyed the recordplayer. He thought of the tactic of designing a recordplayer that would scan the record, find out what type of player it would destroy, and then reassemble itself into some other kind and play the record. You have to have some way of programming the organism to reorganize its DNA while allowing for the DNA that does this programming to be impervious to change. Thus, THAT DNA is now vulnerable since it cannot adapt. Remember, eventually, EVERYTHING is a genetic, not epigenetic, response.

[/ QUOTE ]

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. Sort of a last gasp shotgun into the next generation hoping to get something that can survive what is becoming unsurvivable. Maybe there are things about dna that we don't know about whereby such an emergency operation on it could be done without producing a lot of poorly functioning offspring.

btw, from that link I see this:
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" When exposed to predators, Daphnia water fleas grow defensive spines (right). The effect can last for several generations."
-------------------------------

I assume they mean the effect lasts for several generations even after the predators have been removed. Isn't that an example of the heretical "inheritance of aquired characteristics"? I understand there is no change in the dna in this case. But still there's a characteristic aquired due to environmental conditions that gets passed to the following generation, even though it fades later on. I guess it's not an evolutionary change. However, I have to wonder if they really know that much about changes to the dna. If epigenetics can Turn Off certain dna maybe it can cause it to actually "whither" after enough time.

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

PairTheBoard

Re: Feral Hogs
 

[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
So it's called epigenetics. A recent development in theory which was laughed at when first suggested. I see them talking about "stress" being a factor triggering epigenetic changes. 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.

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? 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?

PairTheBoard

[/ QUOTE ]

It would have to be heritable. I am reminded of a story from Godel, Escher and Bach, where one of the characters was trying to play any possible record, and the other was trying to design records that, when played, destroyed the recordplayer. He thought of the tactic of designing a recordplayer that would scan the record, find out what type of player it would destroy, and then reassemble itself into some other kind and play the record. You have to have some way of programming the organism to reorganize its DNA while allowing for the DNA that does this programming to be impervious to change. Thus, THAT DNA is now vulnerable since it cannot adapt. Remember, eventually, EVERYTHING is a genetic, not epigenetic, response.

[/ QUOTE ]

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. Sort of a last gasp shotgun into the next generation hoping to get something that can survive what is becoming unsurvivable. Maybe there are things about dna that we don't know about whereby such an emergency operation on it could be done without producing a lot of poorly functioning offspring.

btw, from that link I see this:
-------------------------------
" When exposed to predators, Daphnia water fleas grow defensive spines (right). The effect can last for several generations."
-------------------------------

I assume they mean the effect lasts for several generations even after the predators have been removed. Isn't that an example of the heretical "inheritance of aquired characteristics"? I understand there is no change in the dna in this case. But still there's a characteristic aquired due to environmental conditions that gets passed to the following generation, even though it fades later on. I guess it's not an evolutionary change. However, I have to wonder if they really know that much about changes to the dna. If epigenetics can Turn Off certain dna maybe it can cause it to actually "whither" after enough time.

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

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. The ability to quickly adapt is something that itself would usually be selected for.