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Author Topic:   New genes do arise in the genome
Coyote
Member (Idle past 441 days)
Posts: 6117
Joined: 01-12-2008


Message 1 of 7 (489493)
11-27-2008 8:42 PM


Creationists frequently claim that new genes (what they call information) can't arise in the genome.

This seems to be based on the "kinds" idea, where the initial creation was perfect and its genome has been devolving ever since "the curse" due to the effects of sin. (Forgive me if these details are not exact.)

For the purpose of this discussion, we can define genes as "information" in the broad sense. As creationist Carl Wieland notes (in the article cited below):

quote:
[Darwin] did not know, for instance, that what is passed on in reproduction is essentially a whole lot of parcels of information (genes), or coded instructions.

It cannot be stressed enough that what natural selection actually does is get rid of information. It is not capable of creating anything new, by definition.


Science has been finding that the opposite is true. New information (genes) can and do arise in the genome.

This article: Recipes for life: How genes evolve confirms that new genes do indeed arise, and describes some of the mechanisms of how that occurs.

It is difficult to summarize this article, or to include a small number of paragraphs that encapsulate the findings.

Here are three that begin to describe some of the findings:

quote:
The most obvious way for a new gene to evolve is through the gradual accumulation of small, beneficial mutations. Less obvious is how an existing gene that already does something important can evolve into a different gene. The scope for such a gene to change tack without capsizing the organism that carries it is very limited. However, as biologists realised a century ago, this constraint no longer applies when mutations produce an entire extra copy of a gene. ...

Some theoretical biologists think gene copies can also be preserved by other, more subtle, mechanisms, but the real challenge to the classical model comes from actual studies of new genes in various organisms. Earlier this year, in the most comprehensive study of its kind yet, a team led by Wen Wang of Kunming Institute of Zoology in Yunnan, China, looked at several closely related species of fruit fly. By comparing their genomes, Wang was able to identify new genes that have evolved in the 13 million years or so since these species split from a common ancestor.

One of Wang's surprise discoveries was that around 10 per cent of the new genes had arisen through a process called retroposition. This occurs when messenger RNA copies of genes - the blueprints sent to a cell's protein-making factories (see diagram) - are turned back into DNA that is then inserted somewhere else in the genome. Many viruses and genetic parasites copy themselves through retroposition, and the enzymes they produce sometimes accidentally retropose the RNA of their host cells.


I think that this article is important because it is filling in some of the details by which evolution occurs, and because it contradicts a claim often made by creationists (such as Carl Wieland) who claims that "Natural selection adds no information [genes], in fact it reduces it" and "Evolution requires a way to add new information [genes]."

Discuss.

Edited by Coyote, : No reason given.

Edited by Coyote, : No reason given.


Religious belief does not constitute scientific evidence, nor does it convey scientific knowledge.

Replies to this message:
 Message 2 by AdminNosy, posted 11-27-2008 8:59 PM Coyote has responded
 Message 7 by Wounded King, posted 11-28-2008 5:13 AM Coyote has not yet responded

  
AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 2 of 7 (489496)
11-27-2008 8:59 PM
Reply to: Message 1 by Coyote
11-27-2008 8:42 PM


Requires some definition of terms
You haven't defined just what "information" is. It would be hard to understand what is being discussed without that.

This message is a reply to:
 Message 1 by Coyote, posted 11-27-2008 8:42 PM Coyote has responded

Replies to this message:
 Message 3 by Coyote, posted 11-27-2008 9:12 PM AdminNosy has responded

  
Coyote
Member (Idle past 441 days)
Posts: 6117
Joined: 01-12-2008


Message 3 of 7 (489497)
11-27-2008 9:12 PM
Reply to: Message 2 by AdminNosy
11-27-2008 8:59 PM


Re: Requires some definition of terms
Edited per request.

This message is a reply to:
 Message 2 by AdminNosy, posted 11-27-2008 8:59 PM AdminNosy has responded

Replies to this message:
 Message 4 by AdminNosy, posted 11-27-2008 9:49 PM Coyote has responded

  
AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 4 of 7 (489502)
11-27-2008 9:49 PM
Reply to: Message 3 by Coyote
11-27-2008 9:12 PM


Parcels?
You use a quote that genes are "parcels" of "information".

Your quote does not otherwise define information. I don't see any way of telling from this if there is "new" information or not. Nor do I know how much I have to begin with.

It will need more than this to be comprehensible I think.


This message is a reply to:
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Coyote
Member (Idle past 441 days)
Posts: 6117
Joined: 01-12-2008


Message 5 of 7 (489503)
11-27-2008 10:10 PM
Reply to: Message 4 by AdminNosy
11-27-2008 9:49 PM


Re: Parcels?
Edits have been edited. That's the best I can do.

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AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 6 of 7 (489508)
11-27-2008 10:31 PM


Thread moved here from the Proposed New Topics forum.

  
Wounded King
Member (Idle past 2429 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 7 of 7 (489548)
11-28-2008 5:13 AM
Reply to: Message 1 by Coyote
11-27-2008 8:42 PM


I think that this article is important because it is filling in some of the details by which evolution occurs, and because it contradicts a claim often made by creationists (such as Carl Wieland) who claims that "Natural selection adds no information [genes], in fact it reduces it" and "Evolution requires a way to add new information [genes]."

I think these 2 claims are quite distinct and it is their conflation that makes this argument such a misleading one.

I would agree with the idea that Natural selection doesn't add new information as such. The basis of novel genetic sequences is the sort of mutational molecular mechanisms you touch on with your reference. These can be single nucleotide mutations, gene duplications, exon shuffling, retrotransposition, deletions or larger scale genetic changes. Unless one uses a very subjective measure of information, like Gitt's, it is hard to make any argument that these mechanisms can't change the information level of a genome in either direction.

I'd suggest that the only form of information we might consider Natural selection to contribute to would be the sort of complex specified information which Dembski puts forward. It is Natural selection which allows the maintenance of the incremental changes in information produced by mutation and allows these changes to accumulate in such a way as to produce sequences coding for highly specific functions, either regulatory or in terms of their corresponding protein structures. Such information can certainly be considered both Complex and Specific though obviously ID proponents deny that normal molecular mechanisms and evolution can account for it. Even in this case though I would suggest that Natural selection itself is not adding any information but simply tending to maintain beneficial information containing sequences when they arise, and indeed to tend to eradicate detrimental ones when they arise.

Given the higher proportion of deleterious to beneficial mutations observed we might even allow that the action of natural selection in these cases might tend to be the removal of deleterious novel information rather than its maintenance.

The second statement ...

"Evolution requires a way to add new information [genes]."

Is clearly correct, but a singularly flawed argument given all the known mechanisms for new genetic information to arise.

I think you yourself are conflating Natural selection and evolution in a way that is confusing. You have fallen for Wieland's bait and switch.

The really striking lie in Wieland's article, and the one you are actually addressing here, is ...

It has been shown convincingly that observed mutations do not add information, and that mutation is seriously hampered on theoretical grounds in this area.

This is just an outright lie, there is no conceivable way to justify this claim without resorting to most handwavey and subjective definitions of information, which of course is exactly what Wieland does by using Gitt's information 'measure', which is no measure at all but simply a value judgment based on a lot of pre-loaded assumptions in favour of intelligent design.

TTFN,

WK


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