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gluadys -> RE: How do we identify design? (6/3/2008 3:48:01 PM)
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quote:
ORIGINAL: Jhud quote:
Of course there are all kinds of mutations. So what? That is true of any generic term. There are all sorts of automobiles and many ways of travelling. So, is a specific change in the genome a change in the DNA sequence of the genome? Is that a mutation? If not, why not? I thought I was fairly clear there. 'Change' means nothing. Everyone agrees a change to the genome will change an organism. It is the sort of change that is in question. No "change" does not mean "nothing". "Change" means something is different--in this case a sequence of nucleotides. Indeed, your reluctance to answer the question directly raises more questions. First, again, what is a change to the genome? Do mutations change the genome? Can they change the genome? Can the genome be changed without a mutation? In fact, since you raised the term, what is a "genome"? As I understand it a genome is a sort of ideal model of the genetic map of an organism, but does not cite every variation which occurs in every gene in the existing gene pool. But the individual differences among co-members of the same species are due to differences in the actual DNA sequence of individual genes. The fact that I have blue eyes and my children have brown eyes does not mean we have different genomes or even different genes, but that we have differences in the genes that influence pigmentation in the eye. So one must distinguish between changes to genes and changes to the genome itself. Polyploidy changes the genome, but since it is a chromosomal change rather than a sequencing change, I don' t think it is considered a mutation (I stand to be corrected on that.) A gene duplication would be an example of a change to the genome that is also a mutation. And OTOH, many changes in DNA sequences do not change the genome. They only change the way genes are expressed in different individuals. In fact, often, they don't even do that. Mutations in non-coding DNA do not usually generate individual differences. Nor do synonymous mutations. So to answer a question about the definition of a mutation in terms of changes to the genome is really not to answer the question at all. Mutations may or may not affect a genome. They may or may not affect coding genes. What they do affect is a DNA sequence. That is not nothing. It is a change that is observable. What the impact of that change will be, is, of course, a matter of great interest. But that is a separate issue from defining what a mutation is. Is your flip from "mutation" to "genome" an attempted evasion of the original question?
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