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Mutations, can a species adjust the rate of them?

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posted on Sep, 13 2004 @ 02:53 PM
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I was reading the "why are there still monkeys" thread, and thought I would pose this question.

Can a species change it's own rate of mutation?

As organisms have evlolved, there have been periods of more rapid evolution, other times the rate is much slower..
This doesn't actually mean there are more mutations in that period.
It just means that sometimes, one organism has an advantage, and the species can go in that direction.

But what about purposeful mutation? It could be brought on by environmental cues, or by populations of other competeing organisms.

Could there be a "mutation" gene. That turns on and off, when the time is right? It might be an advantage...

Any Ideas here?


[edit on 13-9-2004 by spacedoubt]



posted on Sep, 13 2004 @ 03:05 PM
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the overall mutation rate is controlled by multiple things. Exposure to radiation, chemicals, temperature, etc. But an organism can't control its mutation rate.

Also, keep in mind that species, as a unit, don't have very many characteristics (as opposed to say, the individuals that they are made up of). Mutation rate wouldn't be a species characteristic.

But, as far as turning it 'on and off', well, mutations to sections of the genome that control other large portions of it might be more along the lines of what you are thinking. The rate at which certain events during growth happen can be controlled, and changes to the genes that regulate their rates could be drastic. Tho, in either case, the organism wouldn't have control over this, certainly no more than it has control over the postion of its liver or size of its appendix or something.



posted on Sep, 13 2004 @ 03:47 PM
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Although Nygdan is right about the factors influencing mutation rate, organisms can somewhat affect the mutation rate. Mutations are changes in the DNA. DNA repair mechanisms can undo those changes in some cases. Better DNA repair mechanisms can lower the rate of mutation.

I think the periods of more rapid evolution are in part caused by changing environmental conditions. When all niches are filled, a mutation that takes a organism away from a certain niche will not be good. Natural selection will favour those organisms that stay inside their own comfortable niche. When the environment changes a lot old niches disappear and new niches appear. Natural selection now favours organisms that mutate to fill the new niches. I think this can in part explain the periods of rapid evolution.



posted on Sep, 13 2004 @ 06:13 PM
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Originally posted by amantine
organisms can somewhat affect the mutation rate. Mutations are changes in the DNA. DNA repair mechanisms can undo those changes in some cases. Better DNA repair mechanisms can lower the rate of mutation.

Are you saying that the organisms themselves alter their mutation rate, in the same way that they alter their breathing rate as they fall asleep? I mean, mutation rates change, and even overall mutation rates can be changed by changes in the organism (as in having a slightly less perfect enzyme copying the dna), but would you really say that this is something the organism 'does'? I don't look at it in that way at any rate, tho I can see why you might say it. The organism 'breaks down proteins' during digestion and the like, even tho its a particular set of enzymes doing it.

But either way you're certainly not saying its behavioural no?



posted on Sep, 13 2004 @ 06:24 PM
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I know your post was meant for amantine but.
Here's what I am asking.

If an organism is Stressed, for one reason or another.
Could there be an enzyme, or hormone, that cranks up the mutation rate.
As was said, there are chemicals that can cause mutations..
What if the organism produced these, on it's own..
Doesn't really have to be a conscious effort. just a chemical feedback loop, in a way.

It's just something that I was wondering about..



posted on Sep, 13 2004 @ 06:30 PM
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This is an idea somewhere along the line of "punctuated equilibrium"...except with that theory, it's a matter of guessing when the next mutation will occur...but they usually come along in a time of need...

Controlling whenwe evolve is practically impossible...you'd just as soon kill the world's population by drowning them before one little baby would be born that could breathe underwater...


The lab is about the only place these things can be done - and as we're just now harnessing the power of the human genome, it will be a while before we can make those kinds of advancements...I think the next step of human evolution will not be traditional in the biological evolutionary sense...it will be many different forms of biomechanical "upgrades"



posted on Sep, 13 2004 @ 07:29 PM
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Originally posted by EnronOutrunHomerun
This is an idea somewhere along the line of "punctuated equilibrium"

I think you are misunderstanding gould's idea. Bascially, gould and elderigde were looking at the extant fossil record, and considering mayrs idea (ok, it might not intially have been his idea, I don't know) that species arise in an allopatric mode, with smaller perhipheral populations (being isolated and thus very susecptible to genetic drift, founders effect, and the like) budding off, speciating, and then expanding their formerly small range. Gould and Eldridge figured that when this process is applied to the fossil record, (ie put into the context of inimaginably long geological time) that the resulting pattern is one where new species (although, there is much more detail on what is meant by species in this context) arise 'quickly' (geologically speaking) and replace their parental population.


Having said that, the OP's idea of an organism being 'stressed' and then having more mutations might perhaps occur, but in order for it to be passed on it would have to be a mutation that occurs in the reproductive cells. Fertilization would occur, then the offspring would presumably be under similar stress, and have to be chance have a mutation there also, or something like that. But no, there isn't one 'overall' protein that controls 'mutation rate', although the proteins that are responsible for copy dna and the like would come close to that. In some groups of organisms these proteins have different 'efficiency' rates, so that would be similar, but the effeciency of these proteins tends to be, as far as I know, rather stable in groups. Its obviously a very important set of proteins, and any changes in them could be disasterous (ie failure to replicate dna)



posted on Sep, 13 2004 @ 07:41 PM
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Originally posted by Nygdan
I think you are misunderstanding gould's idea. Bascially, gould and elderigde were looking at the extant fossil record, and considering mayrs idea (ok, it might not intially have been his idea, I don't know) that species arise in an allopatric mode, with smaller perhipheral populations (being isolated and thus very susecptible to genetic drift, founders effect, and the like) budding off, speciating, and then expanding their formerly small range. Gould and Eldridge figured that when this process is applied to the fossil record, (ie put into the context of inimaginably long geological time) that the resulting pattern is one where new species (although, there is much more detail on what is meant by species in this context) arise 'quickly' (geologically speaking) and replace their parental population.

Hmm...I guess so...

From what I understood of his hypothesis, he suggested that evolution was nothing but a "rapid" series of mutations that occur speraticly, often without cause, and as you said...eventually result in replacing the previous generation...

I guess I need to pick up a copy of his book sometime and actually read it instead of going off of what I remember from my courses


But now that I think about it, wasn't his idea put to rest by someone recently?


Odd

posted on Sep, 13 2004 @ 08:42 PM
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Mutant genes that remain recessive for long periods of time only to surface eventually due to some external influence are not unheard of; in fact, they're not really even uncommon. Regulatory genes, they're called... they're the things that keep us from growing from fetuses into the little fishlike creatures they resemble.

History is full of entire populations of organisms suddenly experiencing a drastic change in only one generation. There's no reason why a human couldn't do the same.



posted on Sep, 14 2004 @ 01:56 AM
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Originally posted by Nygdan
Are you saying that the organisms themselves alter their mutation rate, in the same way that they alter their breathing rate as they fall asleep? I mean, mutation rates change, and even overall mutation rates can be changed by changes in the organism (as in having a slightly less perfect enzyme copying the dna), but would you really say that this is something the organism 'does'? I don't look at it in that way at any rate, tho I can see why you might say it. The organism 'breaks down proteins' during digestion and the like, even tho its a particular set of enzymes doing it.

But either way you're certainly not saying its behavioural no?


No, I was simply talking about hereditary DNA repair mechanisms and that differences in these DNA repair mechanisms affect the mutation rate. It might be possible that an organism can control the amount of DNA repair enzymes being created, but I've never heard of that occuring in nature.



posted on Sep, 14 2004 @ 09:52 AM
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Thats generally what I thought you were saying, just wanted to make certain that I wasn't misunderstanding or hadn't missed something (ok, i probably missed something somewhere). Can never be too careful these days, new stuff is being found all the time, and I have a stack of unread Nature sitting nearby.



posted on Sep, 14 2004 @ 12:50 PM
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Originally posted by spacedoubt

If an organism is Stressed, for one reason or another.
Could there be an enzyme, or hormone, that cranks up the mutation rate.

No.

Extreme stress will cause changes in some cells, but in order to get "mutations" it needs to change cells in the ovaries and testes. What extreme stress does is tend to kill the organism early.



posted on Sep, 14 2004 @ 01:26 PM
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Byrd,

Pretty definite answer!
This includes single celled Organisms?
What about Cockroaches, that seem to adjust to pesticides?

There are also some fishes that change sex, according to male to female ratio, that may not be a mutation, but it certainly has an effect on reproductive cells.



posted on Sep, 14 2004 @ 02:16 PM
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Originally posted by spacedoubt
What about Cockroaches, that seem to adjust to pesticides?

The individual is not adjusting. Some members of the population have a pre-existing condition that makes them more resilient to some pesticides. Upon application of said pesticide, the restive ones live and the non-resitive ones die, thus leading to a population wherein more members are resistant. There will, in this new population, be a tendency amoung individuals to vary one way or the other in terms of pesticide resistance; meaning some will be even more resistant, produce more offspring, and the population over time will be more and more resistant. But the individual doesn't change in evolution.

There are also some fishes that change sex


These are changes triggered by hormones I beleive, however, they are what is known as ontogenetic change, not evolutionary or phylogenetic change.

The bit about the reproductive cells changing, what was meant was lets say you have an individual. His head is exposed to radiation, and the cells there are damaged and mutate and he has weirdness growing out of his head. His offspring will be normal, because offspring are produced by a fusion of gametes. If the gametogenic cells (in the testes or ovaries or whatever gonads this individual is carrying around) are exposed to mutagens and their genome is altered, then the offspring will have this mutation.



posted on Sep, 14 2004 @ 07:34 PM
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Thanks Nygdan,

I'm pretty clear on the part about regular cells and the reproductive type.
All your answers are really helpful!

Let me see If I can come up with some other questions..




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