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Author Topic:   Questions on "Random" Mutations
Modulous
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Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 31 of 80 (410284)
07-14-2007 5:46 AM
Reply to: Message 24 by MartinV
07-14-2007 1:59 AM


Re: Dawkins about random mutation
Dawkins (there is no free access anymore to it, but the link to it's transcription is on the bottom of my post) took for granted that random mutation is responsible for dog's diversity.
Dawkins is well aware that dogs have a massive genetic diversity which was tapped into by humans through selective breeding. Dawkins states that this diversity came from mutation, before we started domestication (and obviously, to a lesser extent afterwards). The article you refer to can still be found here.
Someone asked him directly once about an experiment involving evolving fish and how quickly their colours changed. Dawkins said that the diversity was probably already there, rather than mutation occurring during the experiment. You can watch that here (Q & A session)
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 24 by MartinV, posted 07-14-2007 1:59 AM MartinV has replied

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MartinV 
Suspended Member (Idle past 5828 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 32 of 80 (410285)
07-14-2007 6:03 AM
Reply to: Message 31 by Modulous
07-14-2007 5:46 AM


Re: Dawkins about random mutation
That's right Modulous. You have said it more precisely. Dogs had massive genetic diversity before domestification. Lizards and tigers don't possess such genetic diversity and consequently they cannot be domesticated. According Flegr this fact can be explained by a hypothesis that dogs evolved only recently, the other species are evolutionary older and frozen. So or so the case doesn't prove that alleles in dogs arouse by random mutation.
I was questioned also if there was any attempt to create new species by breeding throughout history. Dogs are a good example. They are very diversified but they are the same species. Why using massive breeding many thousands years there are no descendant species? Because selection itself cannot create new species. Breeders know it very well and that's why an idea of selection as source of speciation never occured to them. So simple idea has to wait until midst 19 century to be discovered by Darwin.
On my opinion natural selection just removes extremities and is purely conservative force.
Edited by MartinV, : former student of theology deleted

This message is a reply to:
 Message 31 by Modulous, posted 07-14-2007 5:46 AM Modulous has replied

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Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 33 of 80 (410287)
07-14-2007 6:15 AM
Reply to: Message 32 by MartinV
07-14-2007 6:03 AM


Re: Dawkins about random mutation
According Flegr this fact can be explained by a hypothesis that dogs evolved only recently, the other species are evolutionary older and frozen. So or so the case doesn't prove that alleles in dogs arouse by random mutation.
I have no idea what 'evolutionary older' means. I wasn't attempting to prove that the diversity arose by mutation, I was explaining Dawkins' position.
I was questioned also if there was any attempt to create new species by breeding throughout history.
Yes. Lots of times. Successfully.
Dogs are a good example. They are very diversified but they are the same species. Why using massive breeding many thousands years there are no descendant species?
We have to remember that aggressive artificial breeding reduces genetic diversity. Nevertheless - we do not know there are no descendant species. We'd have to go back 100,000 years and try and breed modern dogs with older dogs to see if they are still the same species.
Even if they could it wouldn't mean anything. Speciation isn't something that HAS to happen.
Because selection itself cannot create new species.
Exactly. Mutation is probably needed in almost all or all cases. The chromosomes have to stop recognizing each other so that germ cells cannot be produced.
So simple idea has to wait until midst 19 century to be discovered by former student of theology Darwin.
What is simple? That variation is required as well as the fact that nature can select? It is simple, but such is the way with science - it always looks simple in hindsight!
On my opinion natural selection just removes extremities and is purely conservative force.
Does anybody disagree? It is a force of keeping what works, a force that can lead to adaptation. It is certainly conservative whereas mutation is radical. The two combined...
Edited by Modulous, : No reason given.

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bluegenes
Member (Idle past 2477 days)
Posts: 3119
From: U.K.
Joined: 01-24-2007


Message 34 of 80 (410290)
07-14-2007 6:45 AM
Reply to: Message 28 by MartinV
07-14-2007 3:21 AM


Re: Dawkins about random mutation
MartinV writes:
The other question is why we can't breed lizards or tigers. Either there are not alleles that can be used for domestication or these species do not mutate.
There's absolutely no reason why we couldn't breed either tigers or lizards. There's considerable variety already in tigers, with the world's largest wild cat, the Siberian tiger, already significantly different from the others. The Sumatran tiger has been in isolation on its island since the last ice age as well, so there's probably quite a lot of variety to go on.
However, nature has already done this in a sense, and the big roarer cats, lions, tigers and leopards, are the end products. All can produce offspring with the others in captivity, and some of the hybrid females are fertile, which means that we could possibly play with introducing lion and leopard genes into some of our new tiger breeds.
What we see in these cats is the result of nature, over perhaps about 2 million years, doing what we've done with dogs (and domestic cats). The genetic differences must be more profound in the wild cats, because the male hybrids seem to be invariably sterile.
The real natural equivalent of our dog breeds could perhaps be the differences within lions, tigers and leopards. There are visible and behavioural differences between African and Asian lions, the Snow Leopard and tropical leopards, and the Siberian Tiger and other tigers as mentioned above.
The big roarer cats are a very good example of varying degrees of divergence from a (relatively speaking) recent common ancestor. Evolution, Martin, whether you like it or not!

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 35 of 80 (410291)
07-14-2007 6:54 AM
Reply to: Message 24 by MartinV
07-14-2007 1:59 AM


Re: Dawkins about random mutation
One of the most claimed and unproved darwinian statement is that behind evolution stands random mutation as the source of novelties.
Which is true by definition.
Breeders would be surprised by such a statement.
Nope.
We cannot breed lizards or tigers
Yes we can. Look at the systematic breeding of tigers with the albino mutation.
But this is obviously just a story:
St Bernards exist, and are the result of selecting desirable mutations, whether or not anyone ever tied a barrel to one.
But dogs are hardly the best example of artificial selection. Ladies and gentlemen, I give you Brassica oleracea.
Edited by Dr Adequate, : No reason given.
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 36 of 80 (410292)
07-14-2007 7:02 AM
Reply to: Message 32 by MartinV
07-14-2007 6:03 AM


Re: Dawkins about random mutation
Dogs had massive genetic diversity before domestification.
Please demonstrate the "massive" genetic diversity of undomesticated Canis lupus as opposed to other species or stop making stuff up.
I was questioned also if there was any attempt to create new species by breeding throughout history.
Yes, it's been done several times.
Breeders know it very well
Why do you keep attributing your delusions to "breeders"?
So simple idea has to wait until midst 19 century to be discovered by Darwin.
Since you don't understand it, it can't be that simple.
On my opinion natural selection just removes extremities and is purely conservative force.
And all biologists have a different opinion, which is backed up by actual data rather than making stuff up.
Edited by Dr Adequate, : No reason given.

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Replies to this message:
 Message 38 by NosyNed, posted 07-14-2007 11:48 AM Dr Adequate has replied

  
Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 37 of 80 (410293)
07-14-2007 7:07 AM
Reply to: Message 28 by MartinV
07-14-2007 3:21 AM


Re: Dawkins about random mutation
It took a lot of time till 19 century that idea of natural selection as one of the sourcees of speciation appeared. Breeders of many generations and civilisation somehow didn't notice the simple fact.
I'll tell you what else they hadn't noticed by Darwin's time:
"Ask, as I have asked, a celebrated raiser of Hereford cattle, whether his cattle might not have descended from long horns, and he will laugh you to scorn. I have never met a pigeon, or poultry, or duck, or rabbit fancier, who was not fully convinced that each main breed was descended from a distinct species. Van Mons, in his treatise on pears and apples, shows how utterly he disbelieves that the several sorts, for instance a Ribston-pippin or Codlin-apple, could ever have proceeded from the seeds of the same tree. Innumerable other examples could be given. The explanation, I think, is simple: from long-continued study they are strongly impressed with the differences between the several races; and though they well know that each race varies slightly, for they win their prizes by selecting such slight differences, yet they ignore all general arguments, and refuse to sum up in their minds slight differences accumulated during many successive generations." --- Darwin, Origin of Species, ch. 1.
Edited by Dr Adequate, : No reason given.

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NosyNed
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Posts: 8996
From: Canada
Joined: 04-04-2003


Message 38 of 80 (410332)
07-14-2007 11:48 AM
Reply to: Message 36 by Dr Adequate
07-14-2007 7:02 AM


Re: Dawkins about random mutation
MV writes:
On my opinion natural selection just removes extremities and is purely conservative force.
DrA writes:
And all biologists have a different opinion, which is backed up by actual data rather than making stuff up.
I think (other than "extremities" being an odd wording) that MV is somewhat correct in this case. If he is talking about the genome at any one point then NS isn't adding to it. In that view it is conservative.
Of course, another view is that NS is reshaping the gene pool over time. In that view maybe it's not so conservative.
Maybe it needs a bit more discussion?

This message is a reply to:
 Message 36 by Dr Adequate, posted 07-14-2007 7:02 AM Dr Adequate has replied

Replies to this message:
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bluegenes
Member (Idle past 2477 days)
Posts: 3119
From: U.K.
Joined: 01-24-2007


Message 39 of 80 (410334)
07-14-2007 12:10 PM
Reply to: Message 38 by NosyNed
07-14-2007 11:48 AM


Re: Dawkins about random mutation
Maybe it needs a bit more discussion?
I think Dr. A's reading of what Martin meant was accurate, Ned. As you say, NS is reshaping the gene pool over time. It does not "just remove extremities". It could be said to remove extremities, if we used the word extremities to mean "characteristics disadvantageous to the organism in any particular environment". However, it's Martin's use of the words "just" and "purely" which give the clue to his meaning.
NS can clearly be a conservative force, and a force for change.

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Dr Adequate
Member (Idle past 284 days)
Posts: 16113
Joined: 07-20-2006


Message 40 of 80 (410357)
07-14-2007 1:22 PM
Reply to: Message 38 by NosyNed
07-14-2007 11:48 AM


Conservative And Adaptive Selection
Conservative selection is where NS wipes out new mutations 'cos the old ones are better, as opposed to adaptive selection. So either MartinV is wrong about biology or he's wrong about biological terminology. Or both.

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taylor_31
Member (Idle past 5923 days)
Posts: 86
From: Oklahoma!
Joined: 05-14-2007


Message 41 of 80 (410406)
07-14-2007 10:49 PM
Reply to: Message 22 by crashfrog
07-14-2007 12:08 AM


The genetic alphabet is only four "letters" long. The most surprising discovery of the human genome project is that the entire human genome is only about 15,000 genes.
My problem, I think, is imagining and "seeing" the long progress from a population of bacteria and their particular attributes to a population of spiders and their particular attributes. Isn't there a great deal more genetic information in a spider than there is in a bacterium? I could see the genome slowly growing and slightly mutating over the eons, but when do the bacteria begin to pick up extra "material"? In a previous thread, I postulated that DNA can "order" a cell to gather exterior material to suit its own purposes. Is that what happens?
If you're wondering what gene it takes to specify a liver, I don't know myself. That would be a question of evolutionary developmentology, I think.
I think that would be wonderful to learn, because I'm very curious about how mutations can affect organisms and how they drive evolution. A book that meticulously describes the history of life, preferably in layman terms, would be helpful. It would probably be speculative, but it might give me an idea of what the real process was like. I've asked for The Selfish Gene for my birthday, so maybe that will help me out.

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Doddy
Member (Idle past 5909 days)
Posts: 563
From: Brisbane, Australia
Joined: 01-04-2007


Message 42 of 80 (410431)
07-15-2007 3:33 AM
Reply to: Message 41 by taylor_31
07-14-2007 10:49 PM


Wrong Dawkins Book
taylor_31 writes:
A book that meticulously describes the history of life, preferably in layman terms, would be helpful.
In that case, you're after the wrong Dawkins book. You'd be better off with The Ancestor's Tale - it does the history of life, although it goes backwards from humans, rather than the opposite, because Dawkins wanted to stress that humans are not the aim of evolution.

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crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 43 of 80 (410494)
07-15-2007 12:10 PM
Reply to: Message 41 by taylor_31
07-14-2007 10:49 PM


Isn't there a great deal more genetic information in a spider than there is in a bacterium?
Yeah, but not a whole order of magnitude more. For instance, compared to the 15,000 genes in the human genome, E. coli has something like 4000 genes.
It takes surprisingly little genetic information, apparently, to describe the difference between you and bacteria.
In a previous thread, I postulated that DNA can "order" a cell to gather exterior material to suit its own purposes. Is that what happens?
Cells are always gathering exterior material while they're alive, because their metabolic processes require a constant influx of food energy and raw materials. The cellular membrane isn't just a piece of Saran wrap holding the cell together; it's studded with little protein "doors" that only work one way. Some of them allow wastes to leave and some of them allow food to enter.
So materials are always on their way in, and as you found out in that other thread, everybody's body - from the spider to you - is essentially made out of exactly the same thing. Sugars, proteins, fats. (These are all examples of macromolecules - large molecules that, like DNA, are made up of combinations of smaller, repeating constituent molecules.)
I think that would be wonderful to learn, because I'm very curious about how mutations can affect organisms and how they drive evolution.
PZ Myers is a evo-devo biologist from my hometown, and he writes a blog about politics and science. During the school year he also posts about genetics and developmentology, and I've found those posts very fascinating and accessible to the layperson. So that could be one more recourse for you: pharyngula | ScienceBlogs

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Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 44 of 80 (410531)
07-15-2007 5:02 PM
Reply to: Message 43 by crashfrog
07-15-2007 12:10 PM


developmentology
I don't think this word means developmental biology, if it means anything at all.
the only link on google using that term in this context is one by you here on EvC.
Aren't there enough creationists making up their own terms without us getting in on the act?
TTFN,
WK

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crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 45 of 80 (410532)
07-15-2007 5:14 PM
Reply to: Message 44 by Wounded King
07-15-2007 5:02 PM


I don't think this word means developmental biology, if it means anything at all.
If the phrase was actually "evolutionary developmental biology", then it would be "evo-dev-bio", now wouldn't it?
Yet, that's not what they call it. Which makes it pretty clear that the field abbreviated as "evo-devo", expanded, would be "evolutionary developmentology", and it should be additionally obvious to anybody with a brain that "developmentology" would be "the study of development."
So, you know, stuff it.

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