On the thread
Natural Limitation to Evolutionary Processes, discussion came up at the end about the nature of mutations and I would like this thread to be all about mutations.
In trying to write this PNT I think I've figured out that there are two main areas of questions I have.
I hope the questions are clear. I will discuss them a bit below.
Since I always get in trouble on science threads and there is no place for this topic to be BUT a science thread I hope I can keep my participation to the role of asking questions.
For starters:
The definition of Mutation at Wikipedia
Mutations are considered the driving force of evolution, where less favorable (or deleterious) mutations are removed from the gene pool by natural selection, while more favorable (beneficial or advantageous) ones tend to accumulate. Neutral mutations are defined as mutations whose effects do not influence the fitness of either the species or the individuals who make up the species. These can accumulate over time. The overwhelming majority of mutations have no significant effect, since DNA repair is able to revert most changes before they become permanent mutations, and many organisms have mechanisms for eliminating otherwise permanently mutated somatic cells.
This definition is clear: Mutations are the DRIVING FORCE OF EVOLUTION.
Here is
another definition:
In the living cell, DNA undergoes frequent chemical change, especially when it is being replicated (in S phase of the eukaryotic cell cycle). Most of these changes are quickly repaired. Those that are not result in a mutation. Thus, mutation is a failure of DNA repair.
Mutations are a failure of some sort, or a mistake.
So, mutations are both the driving force of evolution AND mistakes.
A number of posts on the old thread
Natural Limitation to Evolutionary Processes might be relevant or at least give context from the earlier discussion:
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Percy's 295 and some earlier ones of his I didn't track down, around the 180s. In this post he is mainly complaining about my failure to grasp certain things, and I suppose that will come up here too. I would only like to answer one point: I KNOW that there are no proteins in DNA; the proteins are "coded for" by the sequences of chemicals on the DNA, and I don't know how I gave a different impression but I suppose my language was ambiguous.
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Crash's 296 in which he explains what a gene is. In the process he confirms that pseudogenes are formerly functioning genes, and I think I at least should refer back to this post for orientation from time to time, and maybe his #170 too. He is very good at giving homely analogies to make a point. His 170 got a deserved POTM for its clarity, another one to check out.
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Wounded's 279 about the Solid Gold mutant ram, in which he is showing me that I'm wrong about my guess that this may merely be a variation thrown up from low-frequency alleles in the population. He describes its mosaicism, or the fact that the mutation only shows up in some of the somatic cells. This is a whole area I have hardly any understanding of, and Crash also said, I think in his post #170, that all of us get both our parents' alleles in different cells throughout our bodies -- if I got that right. I thought all our cells were some kind of package of both that defines us. But maybe I have this wrong and I'm not sure how relevant it is to this PNT anyway, but the mutant ram is certainly an interesting case of an apparently beneficial mutation.
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Nosy's 277 He says:
But this is exactly what mutations are. They are changes that produce novel sequences. One may label them mistakes if we think that the gene reproducing process MUST produce perfect copies. It is clear that this would be a VERY BAD thing. These "mistakes" are what makes it possible for ongoing populations of organisms to deal with environmental changes (of all types).
And I'll take off from Nosy's comments into my main concerns about mutations for the purposes of this thread:
BENEFICIAL MUTATIONS?
From the point of view of the ToE, which is that mutations are its driving force, the origin of everything living, of course it must be true that these mistakes are essential, and perfect replication would be a disaster, as Nosy says.
But if the ToE is NOT true, then mutations really probably are mistakes, whose supposed benefits are an illusion, and really simply evidence of the gradual deterioration of all life since the Fall. In this case the fact that most of them have no effect at all just underscores the gradualness of the deterioration process, and the occasional apparently beneficial mutation is a mere anomaly that occurs in the nature of the chemistry involved.
The examples so far given on that thread of supposedly beneficial mutations are to my mind highly questionable.
But of course I was taken to task for my definition of "beneficial" which is too strict apparently as I can't accept most of the examples given as beneficial.
I dunno. We're talking about THE supposed "driving force" of evolution, the system that brought us the eye and the hand and the human brain and in fact the whole stupefyingly elegant system of genetic coding -- it makes your jaw drop to begin to appreciate the mathematical precision involved in the coding process that creates proteins that actually do things in the cells of living things that make all functions possible -- except for those "mistakes" of course. So I have a hard time accepting that whatever produced the incredible coordinated functions and variations of living things has to resort to such trade-offs in dealing with disease, or explaining how so many genetic diseases keep occurring, if the ToE is correct, and evolution really is the amazing system that brought about all the amazing perfections that are obvious despite the errors.
OK, that's my view of the examples of supposed beneficial mutations.
POSSIBLE NON-MISTAKE MUTATION? (as per YEC assumptions as opposed to ToE assumptions I mean)
But there is this other question about mutations for a creationist who believes in the Biblical Flood. What sort of genetic situation could conceivably account for the development of all the observed variation in living things from the few individuals of each Kind that were on the Ark?
ON the old thread I think it was Percy but I may be misremembering, maybe it was Wounded, who said that even if mutations are predictable they are still random the way the six sides of a die come up randomly and yet there are only those six possibilities. My answer to that is that genetic variation is random in THAT sense anyway, as in the linking up of various possible alleles from a large array in the population, and from the options in the combining of germ cells from two parents.
So it is still a possibility in my mind that there is a method to the madness of SOME so-called "mutations" that is really part of the normal reproductive system rather than merely a mistake and could somehow be part of the explanation for (micro) evolution since the ark.
All this could easily get bogged down in context because of the different basic assumptions, the ToE vs YEC, or simply because genetics is too complex and the varieties of mutations complex enough to choke a dinosaur let alone get digested by the likes of me.
So, I hope it is possible to make a thread out of this stuff.
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