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Author Topic:   Can mutation and selection increase information?
Taq
Member
Posts: 7195
Joined: 03-06-2009
Member Rating: 3.1


Message 121 of 222 (816432)
08-04-2017 10:33 AM
Reply to: Message 116 by Vlad
08-04-2017 5:22 AM


Re: Fitness and sexual reproduction
Vlad writes:

Once again, in the world of asexual reproduction, individuals – say, bacteria – are more or less fit. Yet the world of sex is just another pair of shoes: no individual per se is able to reproduce there. Regrettably, only heterosexual (conspecific) pairs are. Wily Mother Nature…

The reproductive success of a bee colony is often dependent on the sterile workers who never reproduce. Group fitness and kin selection in social sexual species is also of importance. You don't have to reproduce in order to pass your genes along. You can also increase the fitness of your relatives.

Some 7-8 decades ago, the founding fathers of the so-called Modern Synthesis had no idea of system properties, system effects, etc. And so they, in good conscience, operated with the anecdotic idea of individual fitness. Let them do. Yet we live in the second decade of XXI century, and reasoning upon the individual fitness, as regards sexual reproduction, appears sheer ferity.
Then once evolutionary theorists acknowledged invalidity of the individual fitness idea, the whole Modern Synthesis construction would collapse like a rickety house of cards. So sad…

The feather display for a single male peacock can influence the distribution of that peacock's genes. You are wrong.

Edited by Taq, : No reason given.


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 Message 116 by Vlad, posted 08-04-2017 5:22 AM Vlad has not yet responded

  
CRR
Member
Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.1


Message 122 of 222 (816463)
08-04-2017 8:47 PM
Reply to: Message 119 by herebedragons
08-04-2017 9:01 AM


Re: random and non-random mutations
You can have a search that is both goal directed and random.

Suppose there are 100 boxes on a table and I'm told there is a chocolate bar in one of them. I go to the table and start opening boxes at random. I have a goal; I want the chocolate; but the search is random.

Similarly when mutations increase in selected regions in response to an environmental stress there is a good chance that the goal is to adapt to the stressor, even if the mutations are essentially random. Since the hypermutation targets certain areas it is likely these areas have a higher probability of producing a favourable mutation. Conversely hypermutation in other areas of the genome are less likely to produce a mutation favourable to adaptation.

This is a hypothesis. There is insufficient evidence at this time to accept it, but there is even less evidence to reject it.

Keep in mind that in order for a mutation to affect fitness, it must affect the organisms ability to reproduce. So while a mutation that codes for the same amino acid may have energetic effects on a bacterium that may slow it's growth rate enough to give it a slight disadvantage compared to others without the mutation, it is unlikely to have a significant effect on larger organism such as humans.

Why not? We are all dependent for health on the correct ratios of many proteins, enzymes, hormones. If these are incorrect then we could suffer illness or a lack of fitness that could affect our ability to survive, attract a mate, and reproduce. A mutation in the germ cell will affect every cell in our body. In fact I have just such a condition.
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Replies to this message:
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 Message 125 by JonF, posted 08-05-2017 8:24 AM CRR has responded
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Tangle
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Posts: 5101
From: UK
Joined: 10-07-2011
Member Rating: 2.2


Message 123 of 222 (816469)
08-05-2017 1:04 AM
Reply to: Message 122 by CRR
08-04-2017 8:47 PM


Re: random and non-random mutations
CRR writes:

Suppose there are 100 boxes on a table and I'm told there is a chocolate bar in one of them. I go to the table and start opening boxes at random. I have a goal; I want the chocolate; but the search is random.

If you want to make this analogy anything at all like mutation and selection you have to

1. Not know that there are either boxes or tables
2. Not know that there could be chocolate in one of them
3. Not know how to open the boxes
4. Not know why you should try to open the boxes
5. Not know that most of the boxes will blow up and kill you if you do open them

Edited by Tangle, : No reason given.


Je suis Charlie. Je suis Ahmed. Je suis Juif. Je suis Parisien. I am Mancunian. I am Brum. I am London.

"Life, don't talk to me about life" - Marvin the Paranoid Android

"Science adjusts it's views based on what's observed.
Faith is the denial of observation so that Belief can be preserved."
- Tim Minchin, in his beat poem, Storm.


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Vlad
Junior Member
Posts: 27
Joined: 06-03-2017


Message 124 of 222 (816477)
08-05-2017 6:33 AM


Individual fitness
Sapienti sat while Pressie’s got a salad in the head. Too bad.
Well, your trouble, guys, is that you still stay then – in the first half of the XX century. You do along with the founding fathers of the mainstream evolutionary doctrine, and you follow their arithmetical mode of thinking. Individual fitness… Immaculate conception… A scream! How many angels can dance on the head of a pin?
But why, anybody is free to stay where he/she pleases. Who cares?
Replies to this message:
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JonF
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Posts: 3969
Joined: 06-23-2003
Member Rating: 2.2


Message 125 of 222 (816481)
08-05-2017 8:24 AM
Reply to: Message 122 by CRR
08-04-2017 8:47 PM


Re: random and non-random mutations
You can have a search that is both goal directed and random.

Yes. So what? We have plenty of evidence that the processes that increases mutation rate are not goal seeking. Naming wildly different processes doesn't affect that.

Similarly

Not at all similarly. Analogies are not evidence. The two processes are totally disssimilar.

when mutations increase in selected regions in response to an environmental stress there is a good chance that the goal is to adapt to the stressor

Not according to the evidence we have.

Got any evidence for your claim?

Didn't think so.

This is a hypothesis. There is insufficient evidence at this time to accept it, but there is even less evidence to reject it.

What evidence have you studied to conclude that there is less evidence to reject it than for it?

[multiple citations required]

I'll start. Mutation as a Stress Response and the Regulation of Evolvability:

quote:
Our concept of a stable genome is evolving to one in which genomes are plastic and responsive to environmental changes. Growing evidence shows that a variety of environmental stresses induce genomic instability in bacteria, yeast, and human cancer cells, generating occasional fitter mutants and potentially accelerating adaptive evolution. The emerging molecular mechanisms of stress-induced mutagenesis vary but share telling common components that underscore two common themes. The first is the regulation of mutagenesis in time by cellular stress responses, which promote random* mutations specifically when cells are poorly adapted to their environments, i.e., when they are stressed. A second theme is the possible restriction of random* mutagenesis in genomic space, achieved via coupling of mutation-generating machinery to local events such as DNA-break repair or transcription. Such localization may minimize accumulation of deleterious mutations in the genomes of rare fitter mutants, and promote local concerted evolution. Although mutagenesis induced by stresses other than direct damage to DNA was previously controversial, evidence for the existence of various stress-induced mutagenesis programs is now overwhelming and widespread. Such mechanisms probably fuel evolution of microbial pathogenesis and antibiotic-resistance, and tumor progression and chemotherapy resistance, all of which occur under stress, driven by mutations. The emerging commonalities in stress-induced-mutation mechanisms provide hope for new therapeutic interventions for all of these processes.

{emphaisi added}

*Remember that to biologists studying mutations "random" means "randiom with respect to fitness".

Edited by JonF, : No reason given.

Edited by JonF, : Fix bolding


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 Message 122 by CRR, posted 08-04-2017 8:47 PM CRR has responded

Replies to this message:
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ringo
Member
Posts: 13726
From: frozen wasteland
Joined: 03-23-2005
Member Rating: 1.7


Message 126 of 222 (816505)
08-05-2017 11:49 AM
Reply to: Message 124 by Vlad
08-05-2017 6:33 AM


Re: Individual fitness
Vlad writes:

Well, your trouble, guys....


YOUR trouble is that you don't pay any attention to rebuttals. Answer some posts and you may be taken seriously.
This message is a reply to:
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RAZD
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Posts: 19085
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.5


Message 127 of 222 (816509)
08-05-2017 12:00 PM
Reply to: Message 125 by JonF
08-05-2017 8:24 AM


Re: random and non-random mutations
\[b\]random*

oopsie

This is a hypothesis. There is insufficient evidence at this time to accept it, but there is even less evidence to reject it.

What evidence have you studied to conclude that there is less evidence to reject it than for it?

There are two aspects to the question as I see it:

  1. is the ratio of beneficial* mutations to non-beneficial mutations greater under stress?

  2. is the ratio of beneficial* mutations per unit of time greater under stress?

I believe (my opinion) the answers are no and yes. The first ratio can even be lower and still have a greater second ratio.

Further I believe (my opinion) this is an evolved mechanism, as organisms that do this will be selected over those that don't, and that it is a "burn the bridges," do-or-die, last ditch effort at survival.

Enjoy

* with regard to "fitness" ... ie survival

Edited by RAZD, : *

Edited by RAZD, : .


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
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Replies to this message:
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Taq
Member
Posts: 7195
Joined: 03-06-2009
Member Rating: 3.1


Message 128 of 222 (816631)
08-08-2017 12:44 PM
Reply to: Message 122 by CRR
08-04-2017 8:47 PM


Re: random and non-random mutations
CRR writes:

You can have a search that is both goal directed and random.

That doesn't change the fact that mutations are random with respect to fitness.


This message is a reply to:
 Message 122 by CRR, posted 08-04-2017 8:47 PM CRR has not yet responded

  
CRR
Member
Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.1


Message 129 of 222 (816724)
08-10-2017 2:17 AM
Reply to: Message 127 by RAZD
08-05-2017 12:00 PM


Re: random and non-random mutations
RAZD writes:

There are two aspects to the question as I see it:

  1. is the ratio of beneficial* mutations to non-beneficial mutations greater under stress?

  2. is the ratio of beneficial* mutations per unit of time greater under stress?

I believe (my opinion) the answers are no and yes. The first ratio can even be lower and still have a greater second ratio.

I believe (my opinion) the answers are maybe and yes.

I suspect that if a part of the genome is targeted for hypermutation then the ratio could change, but I have no other evidence to support or refute that hypothesis at this time.

Further I believe (my opinion) this is an evolved mechanism, as organisms that do this will be selected over those that don't, and that it is a "burn the bridges," do-or-die, last ditch effort at survival.

Which would I think make it a goal directed random search.
This message is a reply to:
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Replies to this message:
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CRR
Member
Posts: 578
From: Australia
Joined: 10-19-2016
Member Rating: 1.1


Message 130 of 222 (816725)
08-10-2017 2:19 AM
Reply to: Message 125 by JonF
08-05-2017 8:24 AM


Re: random and non-random mutations
JonF writes:


You can have a search that is both goal directed and random.

Yes. So what?


Good. at least we can agree on that.
This message is a reply to:
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RAZD
Member
Posts: 19085
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 2.5


Message 131 of 222 (816731)
08-10-2017 7:09 AM
Reply to: Message 129 by CRR
08-10-2017 2:17 AM


Re: random and non-random mutations
Further I believe (my opinion) this is an evolved mechanism, as organisms that do this will be selected over those that don't, and that it is a "burn the bridges," do-or-die, last ditch effort at survival.

Which would I think make it a goal directed random search.

Only if the 'goal' is to mutate, and that doesn't change the "with respect to fitness" issue

RAZD writes:

There are two aspects to the question as I see it:

  1. is the ratio of beneficial* mutations to non-beneficial mutations greater under stress?

  2. is the ratio of beneficial* mutations per unit of time greater under stress?

I believe (my opinion) the answers are no and yes. The first ratio can even be lower and still have a greater second ratio.

I believe (my opinion) the answers are maybe and yes.

If the rate of unchecked mutations doubles and the proportion of beneficial with respect to fitness mutations falls to 51% you still come out ahead, at the cost of a lot of failure and lost energy in reproduction. This is how turning on hypermutation would be a beneficial trait that gets selected, without it being goal oriented.

If it were goal oriented then why isn't it turned on permanently?

If it's an evolved stress response mechanism, then it only occurs during stress.

Enjoy

Edited by RAZD, : .


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
to share.


• • • Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click) • • •

This message is a reply to:
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JonF
Member
Posts: 3969
Joined: 06-23-2003
Member Rating: 2.2


Message 132 of 222 (816734)
08-10-2017 8:29 AM
Reply to: Message 129 by CRR
08-10-2017 2:17 AM


Re: random and non-random mutations
IOW it's a story you made up, you like, and is contradicted by the evidence.

I have no other evidence to support or refute that hypothesis at this time

This is a hypothesis. There is insufficient evidence at this time to accept it, but there is even less evidence to reject it.

Make up your mind.


This message is a reply to:
 Message 129 by CRR, posted 08-10-2017 2:17 AM CRR has not yet responded

  
Taq
Member
Posts: 7195
Joined: 03-06-2009
Member Rating: 3.1


(1)
Message 133 of 222 (816737)
08-10-2017 10:37 AM
Reply to: Message 129 by CRR
08-10-2017 2:17 AM


Re: random and non-random mutations
CRR writes:

I believe (my opinion) the answers are maybe and yes.

I suspect that if a part of the genome is targeted for hypermutation then the ratio could change, but I have no other evidence to support or refute that hypothesis at this time.

I think you know that we need more than "I suspect" and "I believe".

CRR writes:

Which would I think make it a goal directed random search.

That would be an oxymoron. If it is a random search then it is not goal directed. Goal directed means making specific mutations to a specific gene with a known specific outcome.

Edited by Taq, : No reason given.


This message is a reply to:
 Message 129 by CRR, posted 08-10-2017 2:17 AM CRR has responded

Replies to this message:
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New Cat's Eye
Member
Posts: 11761
From: near St. Louis
Joined: 01-27-2005
Member Rating: 1.6


Message 134 of 222 (816756)
08-10-2017 3:42 PM
Reply to: Message 118 by CRR
08-04-2017 8:04 AM


Re: random and non-random mutations
If they occur in response to environmental stress and the increased mutation rate helps the organism to adapt to that stress then possibly it is goal directed.

At the genotypic level, they don't even have to be random in that they're not necessarily stochastic - but that still doesn't mean that they aren't random from the perspective at the phynotipic level.


This message is a reply to:
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Pressie
Member
Posts: 1802
From: Pretoria, SA
Joined: 06-18-2010
Member Rating: 2.2


Message 135 of 222 (816775)
08-11-2017 7:14 AM
Reply to: Message 124 by Vlad
08-05-2017 6:33 AM


Re: Individual fitness
Vlad writes:

Sapienti sat while Pressie’s got a salad in the head. Too bad.

It would have been wonderful if I knew everything. So, what's new?
This message is a reply to:
 Message 124 by Vlad, posted 08-05-2017 6:33 AM Vlad has not yet responded

    
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