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Author Topic:   Evolution is True Because Life Needs It
foreveryoung
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Posts: 879
Joined: 12-26-2011


Message 181 of 188 (671528)
08-26-2012 10:46 PM
Reply to: Message 180 by Percy
08-26-2012 10:17 PM


Re: Silly creationist story
percy writes:

The human genome has about 3.2 billion sites (base pairs), so doing the multiplication we find that the number of mutations that can be expected in every newborn is about 35. The odds of a newborn with no mutations is (1 - 1.110-8)3.2109, which is about 510-16 or less than one in every quadrillion births.

What I am missing here? How do you logically move from the chances of a newborn having zero mutations in one of every quadrillion births to somatic cells in a living human being mutating everytime they divide?

Edited by foreveryoung, : No reason given.


This message is a reply to:
 Message 180 by Percy, posted 08-26-2012 10:17 PM Percy has responded

Replies to this message:
 Message 182 by Percy, posted 08-26-2012 11:26 PM foreveryoung has responded

    
Percy
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Posts: 15563
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.6


(1)
Message 182 of 188 (671530)
08-26-2012 11:26 PM
Reply to: Message 181 by foreveryoung
08-26-2012 10:46 PM


Re: Silly creationist story
Hi ForEverYoung,

Cell division is not a perfect process. It requires copying the DNA, and occasional copying errors are nearly inevitable. The production of both gamete and somatic cells will almost always include mutations. Here's the full paragraph describing specific mutation rates from that webpage at Wikipedia:

Wikipedia on Mutation Rates writes:

In general, the mutation rate in unicellular eukaryotes and bacteria is roughly 0.003 mutations per genome per generation. The highest per base pair per generation mutation rates are found in viruses, which can have either RNA or DNA genomes. DNA viruses have mutation rates between 10−6 to 10−8 mutations per base per generation, and RNA viruses have mutation rates between 10−3 to 10−5 per base per generation. Human mitochondrial DNA has been estimated to have mutation rates of ~3 or ~2.710−5 per base per 20 year generation (depending on the method of estimation); these rates are considered to be significantly higher than rates of human genomic mutation at ~2.510−8 per base per generation. Using data available from whole genome sequencing, the human genome mutation rate is similarly estimated to be ~1.110−8 per site per generation.

It doesn't matter whether it's viruses or prokaryotes or eukaryotes or gametes, there will almost always be mutations because the mutation rate is non-zero and the number of base pairs is at least in the millions and often in the billions. The includes the production of eukaryotic cells during fetal development and subsequent growth during life for human beings.

--Percy


This message is a reply to:
 Message 181 by foreveryoung, posted 08-26-2012 10:46 PM foreveryoung has responded

Replies to this message:
 Message 183 by foreveryoung, posted 08-26-2012 11:37 PM Percy has responded

    
foreveryoung
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Posts: 879
Joined: 12-26-2011


(1)
Message 183 of 188 (671531)
08-26-2012 11:37 PM
Reply to: Message 182 by Percy
08-26-2012 11:26 PM


Re: Silly creationist story
wikipedia writes:

the human genome mutation rate is similarly estimated to be ~1.110−8 per site per generation.

When you multiply the size of the human genome by the mutation rate per site per generation you get 35 mutations per genome per generation. How many cell divisions occur in one spot in the human body in a 20 year generation? If it is significantly greater than 35 than you don't have a mutation roughly occurring everytime a cell divides. For example if one spot in the body has cell division occurring 3500 times in a 20 year period, you have mutations occurring one time in every 100 cell divisions.

Edited by foreveryoung, : No reason given.

Edited by foreveryoung, : No reason given.


This message is a reply to:
 Message 182 by Percy, posted 08-26-2012 11:26 PM Percy has responded

Replies to this message:
 Message 185 by Dr Adequate, posted 08-26-2012 11:55 PM foreveryoung has acknowledged this reply
 Message 186 by Percy, posted 08-27-2012 12:18 AM foreveryoung has not yet responded
 Message 188 by Taq, posted 08-28-2012 3:52 PM foreveryoung has acknowledged this reply

    
Dr Adequate
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(1)
Message 184 of 188 (671533)
08-26-2012 11:48 PM
Reply to: Message 180 by Percy
08-26-2012 10:17 PM


Somatic Mutation Rates
The human genome has about 3.2 billion sites (base pairs), so doing the multiplication we find that the number of mutations that can be expected in every newborn is about 35.

As compared with its parent at the same stage in the lifecycle.

But there are plenty of cell divisions between those two points. If there was just one you'd have a point, also you'd be a bacterium.

Edited by Dr Adequate, : No reason given.


This message is a reply to:
 Message 180 by Percy, posted 08-26-2012 10:17 PM Percy has acknowledged this reply

  
Dr Adequate
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Posts: 15803
Joined: 07-20-2006
Member Rating: 3.4


Message 185 of 188 (671534)
08-26-2012 11:55 PM
Reply to: Message 183 by foreveryoung
08-26-2012 11:37 PM


Somatic Mutation Rates
Quite so. And all the papers I can find on rates of somatic mutation put it much lower than Percy does.

But even given the right figures, Percy would have a point about cancer. Although the mutation rate is lower than he evidently thinks, the number of cell divisions is sufficiently high that if all or even most somatic mutations caused cancer we'd all be dead.


This message is a reply to:
 Message 183 by foreveryoung, posted 08-26-2012 11:37 PM foreveryoung has acknowledged this reply

  
Percy
Member
Posts: 15563
From: New Hampshire
Joined: 12-23-2000
Member Rating: 4.6


Message 186 of 188 (671536)
08-27-2012 12:18 AM
Reply to: Message 183 by foreveryoung
08-26-2012 11:37 PM


Re: Silly creationist story
foreveryoung writes:

When you multiply the size of the human genome by the mutation rate per site per generation you get 35 mutations per genome per generation. How many cell divisions occur in one spot in the human body in a 20 year generation? If it is significantly greater than 35 than you don't have a mutation roughly occurring everytime a cell divides. For example if one spot in the body has cell division occurring 3500 times in a 20 year period, you have mutations occurring one time in every 100 cell divisions.

Dr Adequate mentioned some important clarifications. My example was not for somatic cells but for gametes and the process of human reproduction. I used that example because Wikipedia provided figures for that and not for somatic cells, but the principles are the same. The copying of genetic material, whether free DNA, nuclear DNA, mitochondrial DNA, or RNA, is not perfect. Occasional errors creep in, and in the vast majority of circumstances they do not cause cancer.

--Percy


This message is a reply to:
 Message 183 by foreveryoung, posted 08-26-2012 11:37 PM foreveryoung has not yet responded

    
rueh
Member (Idle past 1046 days)
Posts: 382
From: universal city tx
Joined: 03-03-2008


(1)
Message 187 of 188 (671606)
08-28-2012 9:44 AM
Reply to: Message 172 by barnes
08-26-2012 4:56 PM


Re: Silly creationist story
What I do see in the world is adaptation. The fox through natural selection will begot, a fox, better adapted to survive in an ever changing world, the whole time never changing from a fox. The fox was Created a fox and will stay a fox, just better adapted to carry on as a fox.

That is exactly what the ToE predicts as well. It is only with the accumulation of these minor adaptations over the span of many generations that we get to something that is fox like but not what we would classify as strictly being a fox. No one (other than yourself) has advocated that we should see anything different than that. What the fox experiment shows is that selection can lead to morphological changes. If we know that an animal's morphology can change. What mechanism is there to keep these changes from accumulating in future generations, until we get something that looks like it is descended from a fox but has characteristics that an ancestral fox does not have?

'Qui non intelligit, aut taceat, aut discat'
The mind is like a parachute. It only works when it is open.-FZ
The industrial revolution, flipped a bitch on evolution.-NOFX
It takes all kinds to make a mess- Benjamin Hoff

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Taq
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Posts: 6098
Joined: 03-06-2009
Member Rating: 4.2


Message 188 of 188 (671635)
08-28-2012 3:52 PM
Reply to: Message 183 by foreveryoung
08-26-2012 11:37 PM


Re: Silly creationist story
When you multiply the size of the human genome by the mutation rate per site per generation you get 35 mutations per genome per generation. How many cell divisions occur in one spot in the human body in a 20 year generation? If it is significantly greater than 35 than you don't have a mutation roughly occurring everytime a cell divides. For example if one spot in the body has cell division occurring 3500 times in a 20 year period, you have mutations occurring one time in every 100 cell divisions.

"Here we present, to our knowledge, the first direct comparative analysis of male and female germline mutation rates from the complete genome sequences of two parent-offspring trios. Through extensive validation, we identified 49 and 35 germline de novo mutations (DNMs) in two trio offspring, as well as 1,586 non-germline DNMs arising either somatically or in the cell lines from which the DNA was derived."
http://ukpmc.ac.uk/abstract/MED/21666693

I think it would also be safe to say that you could find more mutations by increasing the tissue types you are sequencing, as well as the age of the donor. However, it doesn't appear to be a crazy number, like 1 million or so somatic mutations.

Edited by Taq, : No reason given.


This message is a reply to:
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