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Author Topic:   Are Point Mutations problematic for ToE?
jar
Member
Posts: 30934
From: Texas!!
Joined: 04-20-2004


Message 16 of 36 (584047)
09-29-2010 10:44 PM
Reply to: Message 15 by seanfhear
09-29-2010 10:39 PM


I would rather call it just one of the mechanisms. It is certainly not a problem, more just one addition step towards understanding.


Anyone so limited that they can only spell a word one way is severely handicapped!
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subbie
Member (Idle past 38 days)
Posts: 3508
Joined: 02-26-2006


Message 17 of 36 (584049)
09-29-2010 10:49 PM
Reply to: Message 15 by seanfhear
09-29-2010 10:39 PM


Well, by definition it must be more of a confirmation since it's not a problem to any degree whatsoever.

Actually, as I think about this more, there's no need to assume homogeneity of the parent population. The only important factor is whether the mutation introduces an allele to the daughter population that wasn't present in the parent population. And, there's also one more situation where that new allele may not necessarily increase the "genetic information" in the population. That is where the mutation eliminates an allele from the population.


Ridicule is the only weapon which can be used against unintelligible propositions. -- Thomas Jefferson

We see monsters where science shows us windmills. -- Phat

It has always struck me as odd that fundies devote so much time and effort into trying to find a naturalistic explanation for their mythical flood, while looking for magical explanations for things that actually happened. -- Dr. Adequate

...creationists have a great way to detect fraud and it doesn't take 8 or 40 years or even a scientific degree to spot the fraud--'if it disagrees with the bible then it is wrong'.... -- archaeologist


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seanfhear
Junior Member (Idle past 2670 days)
Posts: 23
From: California
Joined: 09-28-2010


Message 18 of 36 (584050)
09-29-2010 11:06 PM
Reply to: Message 17 by subbie
09-29-2010 10:49 PM


Would it be appropriate to assume a trait for an allele as an example and to speculate what could be a possible change in the function or structure of an organism if information was lost? Can you think of a simple example?


"Anyone who has the power to make you believe absurdities has the power to make you commit injustices."
Voltaire
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Omnivorous
Member (Idle past 1045 days)
Posts: 3808
From: Adirondackia
Joined: 07-21-2005


Message 19 of 36 (584053)
09-29-2010 11:24 PM
Reply to: Message 12 by seanfhear
09-29-2010 10:05 PM


Re: How About A Trifecta Echo
Hi, Sean, and welcome.

I'd just like to comment on your remark:

seanfhear writes:

I see what you mean by a continueing loss of genetic information. Even if the process went on for a fairly short period of time I guess all you would end up with is an organism with some serious disabilities.

Anglagard was pointing out the flaw in the "point mutations always mean genetic information loss" argument.

When the process goes on long enough, what you have is evolution.


Dost thou prate, rogue?
-Cassio

Real things always push back.
-William James


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seanfhear
Junior Member (Idle past 2670 days)
Posts: 23
From: California
Joined: 09-28-2010


Message 20 of 36 (584055)
09-29-2010 11:38 PM
Reply to: Message 19 by Omnivorous
09-29-2010 11:24 PM


Re: How About A Trifecta Echo
Sorry. My comment was directed to anglagards Also if the experiment is continued for an infinite amount of time would that result in the moths eventually having no genetic information under the always loss scenario. How would they exist with no genes?
I do realize from all the authoritative information thus far that point mutations are a part of the evolutionary process. Thank you.


"Anyone who has the power to make you believe absurdities has the power to make you commit injustices."
Voltaire
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Coyote
Member (Idle past 184 days)
Posts: 6117
Joined: 01-12-2008


Message 21 of 36 (584056)
09-29-2010 11:58 PM
Reply to: Message 20 by seanfhear
09-29-2010 11:38 PM


Welcome
Welcome!

Like your avatar. Very important for radiocarbon dating, which I do a lot of.


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seanfhear
Junior Member (Idle past 2670 days)
Posts: 23
From: California
Joined: 09-28-2010


Message 22 of 36 (584057)
09-30-2010 12:01 AM
Reply to: Message 21 by Coyote
09-29-2010 11:58 PM


Re: Welcome
Thanks. It kinda goes with the name. Check it out.


"Anyone who has the power to make you believe absurdities has the power to make you commit injustices."
Voltaire
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anglagard
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Posts: 2185
From: Socorro, New Mexico USA
Joined: 03-18-2006


Message 23 of 36 (584058)
09-30-2010 12:07 AM
Reply to: Message 22 by seanfhear
09-30-2010 12:01 AM


Re: Welcome
A belated welcome as well, love the sig.


The idea of the sacred is quite simply one of the most conservative notions in any culture, because it seeks to turn other ideas - uncertainty, progress, change - into crimes.
Salman Rushdie

This rudderless world is not shaped by vague metaphysical forces. It is not God who kills the children. Not fate that butchers them or destiny that feeds them to the dogs. Its us. Only us. - the character Rorschach in Watchmen


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Dr Adequate
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Posts: 16085
Joined: 07-20-2006
Member Rating: 10.0


Message 24 of 36 (584060)
09-30-2010 12:30 AM
Reply to: Message 9 by seanfhear
09-29-2010 9:03 PM


Point Mutation Definition
"Point mutation" can mean one of two things. It can, as crashfrog wrote, mean the substitution of one base for another; or it can mean that or the insertion or deletion of a single base; as distinct from larger-scale mutations such as the fusion of two chromosomes.

To avoid confusion you can write "single nucleotide substitution" to mean point mutation in the first sense.

The same reasoning as I presented obviously applies (with suitable amendments) to insertions and deletions as well --- an insertion is reversed by a deletion, and a deletion by an insertion.


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Percy
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Posts: 18309
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.7


Message 25 of 36 (584076)
09-30-2010 4:11 AM
Reply to: Message 18 by seanfhear
09-29-2010 11:06 PM


seanfhear writes:

Would it be appropriate to assume a trait for an allele as an example and to speculate what could be a possible change in the function or structure of an organism if information was lost? Can you think of a simple example?

One good example is vitamin C synthesis in humans. A single point mutation, in this case a deletion, caused a frame shift in the GULO gene responsible for the synthesis of vitamin C. A frame shift is what happens when a single nucleotide is inserted or deleted.

A frame shift works like this. Say you have this simple nucleotide sequence that I've divided into triplets:

TAG / CAT / GCC

Now let's perform a single nucleotide deletion, let's say the 2nd nucleotide gets deleted. We're now left with this:

TAC / ATG / CC

The loss of a single nucleotide has caused the framing of codons to shift, hence the name frame shift mutation. TAG has become TAC, CAT has become ATG, and GCC has become an incomplete codon CC. As you can see, a single nucleotide deletion has the potential to completely change the codon sequences and thereby the protein it is responsible for.

This is in essence what happened somewhere in the distant evolutionary ancestry of apes. A frame shift mutation in the GULO gene responsible for the synthesis of vitamin C experienced the deletion of a single nucleotide that resulted in a premature stop codon. In humans vitamin C synthesis never completes because of the premature stop codon. We have to get all our vitamin C from what we eat.

Here's a comparison of the same subsequence of the rat and human GULO gene. To make it easier to interpret I've included the human sequence twice, once with a dash where the cytosine nucleotide was, and then again with the frame shift:

Rat:   GTA / GAG / GTG / CGC / TTC / ACC / CGA / GGC / GAT / GAC / ATT / CTG / CTG / AGC / CCC
Human: GTG / GGG / GTA / CGC / TTC / ACC / TGG / AG- / GAT / GAC / ATC / CTA / CTG / AGC / CCC (without frame shift)
Human: GTG / GGG / GTA / CGC / TTC / ACC / TGG / AGG / ATG / ACA / TCC / TAC / TGA / GCC / CC (with frame shift)
Single cytosine nucleotide deletion------------^

Sorry it's so wide.

--Percy

Edited by Percy, : Reduce width by using less of the nucleotide sequence.

Edited by Percy, : Typo.


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caffeine
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Posts: 1600
From: Prague, Czech Republic
Joined: 10-22-2008
Member Rating: 2.4


Message 26 of 36 (584082)
09-30-2010 6:41 AM
Reply to: Message 10 by anglagard
09-29-2010 9:07 PM


Re: How About A Trifecta Echo
I don't think this is particularly useful example since (as far as I know), there's no relevant mutating going on here. The light and dark morphs of the moth already existed in the population before northern England was turned into a grim, smog-caked wasteland. All that happened was a change in frequencies as selection favoured light, then dark, then light individuals again.
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anglagard
Member
Posts: 2185
From: Socorro, New Mexico USA
Joined: 03-18-2006


Message 27 of 36 (584084)
09-30-2010 7:35 AM
Reply to: Message 26 by caffeine
09-30-2010 6:41 AM


Re: How About A Trifecta Echo
Maybe so, maybe not - Phish


The idea of the sacred is quite simply one of the most conservative notions in any culture, because it seeks to turn other ideas - uncertainty, progress, change - into crimes.
Salman Rushdie

This rudderless world is not shaped by vague metaphysical forces. It is not God who kills the children. Not fate that butchers them or destiny that feeds them to the dogs. Its us. Only us. - the character Rorschach in Watchmen


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barbara
Member (Idle past 2880 days)
Posts: 167
Joined: 07-19-2010


Message 28 of 36 (584091)
09-30-2010 9:10 AM
Reply to: Message 27 by anglagard
09-30-2010 7:35 AM


Re: How About A Trifecta Echo
Lets say there was a large population of one type of species and there was a stream running down the middle until eventually it became a wide river that separated the population in half. Wouldnt this create a reduction in gene flow for both sides of the river? What is observed is that each population changes over time until they have little resemblance to each other and are classified under a new name. How did they obtain these new genes?
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AZPaul3
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Posts: 3813
From: Phoenix
Joined: 11-06-2006
Member Rating: 3.0


Message 29 of 36 (584094)
09-30-2010 9:42 AM
Reply to: Message 28 by barbara
09-30-2010 9:10 AM


A River Runs Through It
Mutation/Selection. Since there is no flow between the separated populations all new versions of the alleles, any mutations that survive, will exist solely within the one population in which it arose and will not reach the other side of the river. Over a few thousand generations the accumulation of differences can be enough to consider them separate species.

Edited by AZPaul3, : sub-title


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Blue Jay
Member (Idle past 775 days)
Posts: 2843
From: You couldn't pronounce it with your mouthparts
Joined: 02-04-2008


Message 30 of 36 (584099)
09-30-2010 10:26 AM
Reply to: Message 14 by subbie
09-29-2010 10:23 PM


Population or Individual?
Hi, Subbie.

subbie writes:

Obviously the total "genetic information" in the population will increase...

I agree with you on this perspective, and I've used this argument before too. But, thinking about it now, I don't know this is really a useful argument, since, on the population scale, a mutation is essentially defined as an increase in information. Obviously, this isn't what creationists object to at all.

I think, in order to get at what creationists object to, you have to show an information increase in relation to the same gene before it mutated. But, then you get all the definition problems about what counts as "more" or "less" information.

The best way to deal with this mess is what Dr A and Percy did: a demonstration that the objection is invalid no matter how you define "information."

The only way to defeat their argument is to imply some sort of mechanism that assesses whether a "proposed" mutation will add or subtract information, and forbids those that will add, but this idea seems stupid.


-Bluejay (a.k.a. Mantis, Thylacosmilus)

Darwin loves you.


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