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Author Topic:   is the advancement of macro evolution without hick up?
Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


(1)
Message 6 of 41 (548412)
02-27-2010 3:04 PM
Reply to: Message 1 by SHEKINAH
02-27-2010 4:47 AM


You are being confused by a naive idea of species. You are implicitly taking "is the same species as" to be what mathematicians would call a transitive relation like "has the same number of legs as". So if Adrian has the same number of legs as Beth who has the same number of legs as Charles who has the same number of legs as Dawn who has the same number of legs as Edward who has the same number of legs as Francine, who has the same number of legs as George who has the same number of legs as Heidi, then it follows that Adrian has the same number of legs as Heidi.
But a relation does not have to be transitive. Consider the relation "lives in the same neighborhood as". It is perfectly possible for Adrian to live in the same neighborhood as Beth, who lives in the same neighborhood as Charles who lives in the same neighborhood as Dawn who lives in the same neighborhood as Edward who lives in the same neighborhood as Francine who lives in the same neighborhood as George who lives in the same neighborhood as Heidi --- and yet for Adrian and Heidi to live in different neighborhoods.
"Is the same species as" is a relation of the second kind. One can see this by considering that for two organisms to be the same species, they do not have to have identical genomes, just genomes in the same "genetic neighborhood", as it were.
---
About the evolution of sex --- there are organisms which can either reproduce sexually or asexually. Anlso, there are organisms which can reproduce asexually or in a manner that involves lateral gene transfer, which may be considered a more primitive form of sex.

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Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 29 of 41 (548761)
03-01-2010 4:22 PM
Reply to: Message 27 by slevesque
03-01-2010 3:16 PM


Re: We Are All Mutants
I'll look into this then, but you could start by explaining to my layman mind the difference between biochemical and biological functionality.
I think the point is that just because most DNA is transcribed into mRNA doesn't necessarily mean that the mRNA is then translated into proteins. In fact, it can't be --- compare the sheer size of (for example) human DNA with the number of human proteins. Then consider that that number is inflated by alternative gene splicing.
Some of those transcripts might be doing something else besides serving as mRNA in the strict sense, but if they are, it's going to be something astonishingly subtle, because we can after all knock out chunks of non-protein-coding DNA without any observable effects.

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Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 30 of 41 (548763)
03-01-2010 4:29 PM
Reply to: Message 25 by slevesque
03-01-2010 1:36 PM


Re: We Are All Mutants
If the vast majority of mutations are only slightly deleterious and are therefore not exposed to selection ...
A big if.
There is no way ot filter them out of the gene pool ...
Consider that the more these hypothetical mutations accumulated in a genome, the more likely it would become that the next mutation will be slightly beneficial. Even chance alone would establish an equilibrium.

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Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 33 of 41 (548780)
03-01-2010 7:03 PM
Reply to: Message 32 by ZenMonkey
03-01-2010 4:47 PM


Re: We Are All Mutants
This may already have been answered a dozen times over, but isn't it the case that apparently neutral mutations that have been carried along in the genome for whatever reason can then capitalize on additional mutations that have beneficial effects but that might otherwise not have been possible? Actually, isn't that what you're already saying here?
No, I'm thinking of back mutations and other compensatory mutations. The more errors there are, the more likely it becomes that a random change will fix one of them. This leads to a stable equilibrium.
I'd make a computer model if there were any remotely evidenced figures known, but there aren't: the creationist fandango around this subject requires that the effect of the mutations they're talking about should by definition of these mutations be so small that no-one can even tell that any effect exists, and it is of course impossible to measure the frequency of such events or to distinguish them from neutral mutations --- i.e. to find out if they actually exist.
(This reminds me of certain other branches of Christian apologetics.)
Edited by Dr Adequate, : No reason given.

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Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 36 of 41 (548805)
03-01-2010 10:39 PM
Reply to: Message 35 by subbie
03-01-2010 10:18 PM


Re: "junk DNA" now called "non-coding DNA"
Personally, I think I'll stick with "junk DNA."
It introduces an ambiguity invented by creationists. First they pretend that "junk DNA" means all non-coding DNA, then they'll point out that some non-coding DNA is functional, which was of course discovered by evolutionists, then they'll explain that it's evolutionist dogma that all non-coding DNA is "junk", an hence non-functional ... well, you know how it goes. Creationists, eh?
It's best to distinguish between non-coding DNA and non-functional DNA, and leave the creation of ambiguity by the use of the word "junk" to the people who really need ambiguity.

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Dr Adequate
Member (Idle past 285 days)
Posts: 16113
Joined: 07-20-2006


Message 37 of 41 (548806)
03-01-2010 10:40 PM
Reply to: Message 35 by subbie
03-01-2010 10:18 PM


Re: "junk DNA" now called "non-coding DNA"
dp
Edited by Dr Adequate, : No reason given.

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