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Author Topic:   Ratio of Deleterious Mutations to Beneficial Ones
NosyNed
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Posts: 8788
From: Canada
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Message 16 of 35 (719371)
02-13-2014 5:44 PM
Reply to: Message 15 by NoNukes
02-13-2014 5:11 PM


Neutral -- maybe not
The fact is that most human mutations are somewhere close to neutral with respect to fitness. We know this because every human has mutations.

I think this is leaving something out of the measurement. For living humans the mutations are somewhere close to neutral perhaps.

But what about the 50% or more who don't survive the first few weeks of gestation? We haven't measured how much of those failures to survive is due to mutations so we don't know but it might well be that 50 % of the mutations off the top are deleterious.

After that initial ruthless selection we are then left with neutral, mildly deleterious and beneficial.


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Taq
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Member Rating: 3.9


Message 17 of 35 (719372)
02-13-2014 5:52 PM
Reply to: Message 16 by NosyNed
02-13-2014 5:44 PM


Re: Neutral -- maybe not
I think this is leaving something out of the measurement. For living humans the mutations are somewhere close to neutral perhaps.

A much better way to put it is that 80-90% of our genome is accumulating mutations at a rate that is consistent with neutral drift which would indicate that the vast majority of mutations do not affect fitness to the point that natural selection can see the difference.


This message is a reply to:
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NosyNed
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Posts: 8788
From: Canada
Joined: 04-04-2003
Member Rating: 3.8


Message 18 of 35 (719375)
02-13-2014 6:33 PM
Reply to: Message 17 by Taq
02-13-2014 5:52 PM


Re: Neutral -- maybe not
A much better way to put it is that 80-90% of our genome is accumulating mutations at a rate that is consistent with neutral drift which would indicate that the vast majority of mutations do not affect fitness to the point that natural selection can see the difference.

That may be perfectly fine as one way of looking at it. And I find that a very interesting number. Thanks for it.

However, I think the context here is the rate of all kinds of mutations at all points. That means not just in the germ line and not just in the living individuals we may study.

From a reasonable evolutionary perspective it is valid to say that the mutations mostly hover around neutral which your neutral drift information supports.

But we are discussing this with a creationist who claims that "all", "most", "many" or some such portion of mutations are harmful. And from one perspective they may be right. Maybe (I think we don't have the numbers ) harmful mutations are actually in the majority.

Maybe it is worth pointing that possibility out too. This now leads to the recognition of the effect of selection. If the failure of a large percentage of pregnancies is actually due to mutations it demonstrates the power of selection to weed out those mutations.

Without knowing the actual numbers it is clearly possible to conclude that if an individual starts off with a genome that contains a very seriously bad mutation they will obviously not pass the selection filter. In the case of humans we manage to thrive while loosing about half of all fertilization to spontaneous abortions. Since we can manage with that it seems clear that very deleterious mutations can be in the majority and still not be a long term threat to a species and not be of any concern to the evolutionary process.

Edited by Admin, : Fix quote.


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Taq
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Member Rating: 3.9


Message 19 of 35 (719377)
02-13-2014 6:50 PM
Reply to: Message 18 by NosyNed
02-13-2014 6:33 PM


Re: Neutral -- maybe not
But we are discussing this with a creationist who claims that "all", "most", "many" or some such portion of mutations are harmful.

They should be asked to supply evidence to back those claims.

It may be fair to say that a large percentage of the mutations that change amino acid sequence are deleterious, and that is often where the misunderstandings begin.

If we are born with 50 mutations, and 3% of the genome is translated into protein, this would mean that only 1 or 2 mutations occur in the coding portion of those genes. Each one would have about a 70% chances of changing the amino acid sequence, so about 1 per person. Already, we see that only 2% of mutations (at least for common substitution mutations) really have a chance of being seriously deleterious.

The real deleterious mutations are probably indels and recombination events that happen in coding regions. Indels that change the number of bases in a gene by a number indivisible by three will change more than just one amino acid due to a frame shift, as one example.

If the failure of a large percentage of pregnancies is actually due to mutations it demonstrates the power of selection to weed out those mutations.

My own suspicion is that this isn't the case. We are a somewhat promiscuous species, so there is selective pressure to keep our fecundity a little lower. The mutations that may be responsible for the rate of spontaneous abortions in humans are probably already present in the mother and father, and have been selected for. Again, this is my own speculation and I really don't have anything to back it up with just yet.

Edited by Taq, : No reason given.

Edited by Admin, : Fix spelling: promiscious => promiscuous


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Faith
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From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 20 of 35 (719381)
02-13-2014 7:56 PM
Reply to: Message 15 by NoNukes
02-13-2014 5:11 PM


The fact is that most human mutations are somewhere close to neutral with respect to fitness. We know this because every human has mutations. It may be that most mutations that have some significant fitness impact are deleterious rather than beneficial, but given that such mutations are selected against, I would expect that even lop sided ratios of deleterious vs beneficial mutations would not stop the process of evolution.

Are you talking about the kinds of mutations that occur in the body but not the reproductive cells or both or what?

How are they selected against?

ABE: Since we're all guessing, my guess would be that in some sense the vast majority are deleterious but not severe enough to be selected against and those mutations are going to get passed on along with all the other alleles, and any deleterious effects are going to show up generations later.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


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Faith
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Posts: 25595
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 21 of 35 (719382)
02-13-2014 8:01 PM
Reply to: Message 19 by Taq
02-13-2014 6:50 PM


Re: Neutral -- maybe not
It's all guesswork, isn't it? Seems to me I've seen threads where it's been affirmed by evolutionists that the vast majority of mutations are deleterious, and I've seen everything else. Estimate this, estimate that. You guys really don't know.
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JonF
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Member Rating: 3.3


Message 22 of 35 (719386)
02-13-2014 8:16 PM
Reply to: Message 21 by Faith
02-13-2014 8:01 PM


Re: Neutral -- maybe not
You haven't seen any such admission, because it would be a lie.

UABF.


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NosyNed
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Posts: 8788
From: Canada
Joined: 04-04-2003
Member Rating: 3.8


Message 23 of 35 (719387)
02-13-2014 8:26 PM
Reply to: Message 20 by Faith
02-13-2014 7:56 PM


Selected against
Since we're all guessing, my guess would be that in some sense the vast majority are deleterious but not severe enough to be selected against and those mutations are going to get passed on along with all the other alleles, and any deleterious effects are going to show up generations later.

Actually if they are not selected out then they are, for practical purposes, not deleterious. If they show up generations later and they have finally reached a number or an environment were they are, for practical purposes, deleterious and are selected out.

Remember, many mutations are both deleterious and advantageous. The phenotype of a Swahili cattle herder is very advantageous in southern Africa but very deleterious in the high arctic.


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NoNukes
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Posts: 9723
From: Central NC USA
Joined: 08-13-2010
Member Rating: 3.0


Message 24 of 35 (719396)
02-13-2014 10:02 PM
Reply to: Message 20 by Faith
02-13-2014 7:56 PM


Are you talking about the kinds of mutations that occur in the body but not the reproductive cells or both or what?

I'm talking about the genetic changes that are inheritable. Changes which are not inheritable can only affect an individual.

How are they selected against?

Is this a serious question? I don't see how it could be.

Edited by NoNukes, : No reason given.


Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846)

I believe that a scientist looking at nonscientific problems is just as dumb as the next guy.
Richard P. Feynman

If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass


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Faith
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Posts: 25595
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 25 of 35 (719397)
02-13-2014 10:10 PM
Reply to: Message 24 by NoNukes
02-13-2014 10:02 PM


By miscarriage I guess?
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Faith
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Posts: 25595
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 26 of 35 (719398)
02-13-2014 10:13 PM
Reply to: Message 23 by NosyNed
02-13-2014 8:26 PM


Re: Selected against
The problem is that many deleterious mutations are NOT selected out; they produce genetic disease that a person may simply have to live with. If the disease is horrible enough then the person will suffer for years and eventually die of it. Is that what is meant by "selection?"
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dwise1
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Posts: 2863
Joined: 05-02-2006
Member Rating: 4.2


(1)
Message 27 of 35 (719419)
02-13-2014 11:53 PM
Reply to: Message 21 by Faith
02-13-2014 8:01 PM


Re: Neutral -- maybe not
Estimate this, estimate that. You guys really don't know.

Faith, population genetics is highly mathematical. It mainly deals with statistical analysis and probability analysis. It involves determining the probabilities of things happening within populations.

You claimed to know and be using population genetics, yet you obviously don't possess the most basic knowledge about that discipline. Were you lying to us?


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Faith
Member
Posts: 25595
From: Nevada, USA
Joined: 10-06-2001
Member Rating: 1.0


Message 28 of 35 (719426)
02-14-2014 12:09 AM
Reply to: Message 27 by dwise1
02-13-2014 11:53 PM


Re: Neutral -- maybe not
I use the basic concepts, not the mathematics, and I'm not interested in learning any of the sciences to that extent, it would just be a waste of time. I take what makes sense on my model.

ABE: But since you changed the subject, let me repeat the post you were ostensibly answering but didn't:

It's all guesswork, isn't it? Seems to me I've seen threads where it's been affirmed by evolutionists that the vast majority of mutations are deleterious, and I've seen everything else. Estimate this, estimate that. You guys really don't know.

Lotta guesswork, nothing really solid is known about mutations.

Edited by Faith, : No reason given.

Edited by Faith, : No reason given.


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frako
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Posts: 2701
From: slovenija
Joined: 09-04-2010


(1)
Message 29 of 35 (719448)
02-14-2014 2:57 AM
Reply to: Message 26 by Faith
02-13-2014 10:13 PM


Re: Selected against
The problem is that many deleterious mutations are NOT selected out; they produce genetic disease that a person may simply have to live with. If the disease is horrible enough then the person will suffer for years and eventually die of it. Is that what is meant by "selection?"

That's because you are including human medicine in your logic. Sure if a human baby is borne without the ability to produce insulin he can have a normal life with treatment. but if a deer somewhere in the wild is borne with the same mutation it will die before it gets to procreate. hence weeding out that bad mutation from the population. And even if by some miracle it gets to procreate its children are still going to have a much higher chance of not procreating weeding the mutation out eventually.


Christianity, One woman's lie about an affair that got seriously out of hand

What are the Christians gonna do to me ..... Forgive me, good luck with that.


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AZPaul3
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Posts: 3428
From: Phoenix
Joined: 11-06-2006


(1)
Message 30 of 35 (719459)
02-14-2014 8:31 AM
Reply to: Message 28 by Faith
02-14-2014 12:09 AM


How dumb do you think we are?
Don't answer that. It was rhetorical.

Lotta guesswork, nothing really solid is known about mutations.

Oh BULLSHIT!

Come on, Faith. Thousands of highly intellegent humans have been studying this stuff for a century now and you have the unmitigated gall to say they are all just so damn dumb?

Here, Faith. Learn something very basic about mutations that actual intellegent people already know.

Better, yet, Faith, learn how the vast majority of dilitarious mutations are culled from the human genepool.

And here is information, as in real data, facts, hard evidence of the rise and spread of benficial mutations including eamples of "series of mutations that 'build on one another' to add new metabolic pathways for the organism." That means the mutational developement of real new genetic information in the organism, Faith, dispite your insistance that this is impossible. If these are too technical for you there is a reason for that. All those smart people you think are so st*upid know a hell of a lot more about this shit than do you.

Lotta guesswork, nothing really solid is known about mutations.

That's assinine, Faith. Stop saying this kind of crap. You're better than this.

Edited by AZPaul3, : oops


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