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Author | Topic: No genetic bottleneck proves no global flood | |||||||||||||||||||||||||||||||||||||||
AZPaul3 Member Posts: 8513 From: Phoenix Joined: Member Rating: 5.3
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Sorry, Tanypteryx. ONE mutation for black fur in a population absolutely devoid of that allele must must show up just in time for when it's needed, against astronomical odds. Really? What makes you think this mutation hadn't happened some thousands of generations past? Or only once? Or one mutation instead of 3 or 4 in multiple sets of mousie fur color genes? Can you honestly say that this dark fur mutation(s) hadn't popped up before ... in a population of hundreds of thousands ... with a sprinkling of a few here and there every generation for many, many generations involving multiple different genes in multiple different ways? Why do you assume that evolution all of a sudden, one time, went ... POOF! You're black, Mouse! ... and that it happened at "just the right time"? Might it be that dark fur conveyed no survival/reproductive advantage in the lighter environs, thus did not become a significant attribute of the population? Might it be that once the black lava fields arrived these very few expressions of dark fur now conveyed that survival/reproductive advantage and thus has now, a few hundred generations later, become a dominate feature of the population? Can you guarantee that, today, a linage of dark furred mousies cannot have a mutated lighter furred oddball in the family, and that maybe, over a population of hundreds of thousands, this happens some small number of times in each generation? What do you think would happen to the population if, say, the Magratheans layered a permanent light saddle-brown spray paint over the area? Maybe the light saddle-brown micies would have the advantage and become the dominate attribute in, let's say, 200 generations or so? Of course not. That's ridiculous. The Maratheans don't have spray paints! Edited by AZPaul3, : No reason given. Edited by AZPaul3, : No reason given.
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AZPaul3 Member Posts: 8513 From: Phoenix Joined: Member Rating: 5.3
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Why should any particular mutation be expected, AZPaul? Since I was saying quite the opposite I fail to see where this came from. The point is that specific mutations cannot ever be expected. But, do not take this to mean that variation as a result of mutation(s) is not expected because it most definitely is expected. As you well know all populations exhibit quite wide variations in almost every attribute present from fur color to digestive efficiency to dick and boob size. What you don't believe is that these variations are initiated as a result of mutation(s) in a single individual giving rise to new alleles, new genetic variation. But that is your own religious hangup that has no relation to reality so you have to live with that, not us. Keep in mind that a darker-fur attribute in a population as large as the pocket moosies will (infrequently) occur. Further, it will occur a few times in each generation and, most probably, NOT be the result of the same mutation(s) in each such individual. Taq is correct. Any specific mutation occurs first in one specific individual. Your misinterpretation of this to insistence that dark fur could occurred only once by only the one mutation and then only when it would be beneficial is bogus. Taq's mutation causing dark fur may be (and in a population the size of the pocket mieces, most probably is) just one of many different ways to accomplish the same thing: dark fur. And each different way to make that attribute starts, as Taq said, with mutation(s) to one initial individual. How far that specific trait spreads in the total population is dependent upon the totality of the selective pressures on the population. So when the dark lava arrives this same process continues and you then have it right:
quote: So Taq is right. New alleles mutate into a population through one specific individual. But you take it too damn far with your faulty interpretation of what he said and the bogus probability assessment that this only happened once in one way and only just in time. That IS NOT what Taq said. Edited by AZPaul3, : No reason given. Edited by AZPaul3, : No reason given.
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AZPaul3 Member Posts: 8513 From: Phoenix Joined: Member Rating: 5.3
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You can't just decide what the words mean ... That is correct, in this specific context, you cannot. Mutations have always been deleterious, beneficial or neutral with respect to fitness. That means that any phenotypic trait that results from the mutations hinders, enhances or has no effect on the individuals ability to survive and reproduce in a specific environment. The fur-color example is classic. The same mutations (darker fur) are deleterious in one environment (lighter ground) and beneficial in another (lava field). The mutations affect that individual's fitness in that specific environment. This changes your point that:
quote: Neutral mutations would not alter fitness. But if we assume (in the matter under discussion) that darker fur in a lighter environment detracts from fitness then darker fur in a lighter environment is always termed deleterious and can never be considered neutral. It has too great an effect, and a direct effect, on the individual's fitness. So you are right. Neutral mutations would not make dark fur in a light environment, but not for the reasons you think. Your idea from message 105:
quote: ... is terribly wrong and needs to change. All mutations are always defined by their effects on the individual's fitness (read "selection"). The result of the mutations may very well change the resultant protein coded by that allele (change its function), and may well change some attribute of the phenotype. But if the phenotype differences do not affect the individual's fitness then the mutations that under lay that change are termed "neutral". And, furthermore, this assessment of the same mutations effects on fitness may very well change with a change in environment. [emphasis] In defining mutations as deleterious, beneficial or neutral it does not matter how the allele function is altered. The only thing that matters is the resulting fitness of the individual. [/emphasis] This is how deleterious, beneficial and neutral mutations have always been defined in every discussion, in every book and on every site. Throughout all the discussions on this board these definitions with respect to fitness have always been the meanings of those words. If you have been using some other idea of what those words mean then you have been very wrong. Nosey and Tany are correct. You need to rethink your stance with respect to the actual definitions of these words and bring your discussions in line with the accepted meanings everyone else in the entire world has been using for decades. Edited by AZPaul3, : No reason given. Edited by AZPaul3, : No reason given. Edited by AZPaul3, : No reason given. Edited by AZPaul3, : hoo boy. I'll never get this right!
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AZPaul3 Member Posts: 8513 From: Phoenix Joined: Member Rating: 5.3
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So there is always a change in the phenotype as a result of ANY mutation? Where did this come from? I never said that. There can be code changes in an allele that do not change the protein being produced. In that case the mutations can not alter the phenotype.
That is the only point that has mattered in how I've used the term. Then, in a deep technical sense, you are still wrong. The mutation is labeled "neutral" not because the protein did not change but because the change did not affect the individual's fitness. Edited by AZPaul3, : No reason given.
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AZPaul3 Member Posts: 8513 From: Phoenix Joined: Member Rating: 5.3
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You are missing the point.
The point is not whether a protein is changed or not or what you call it if it does or doesn't. The point is only what effect the change has on fitness. Pick a change, any change. Does it affect fitness up, down or sideways in some specified environment? There then you have beneficial, deleterious and neutral. Do not add anything else to the mix. Edited by AZPaul3, : added environment.
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AZPaul3 Member Posts: 8513 From: Phoenix Joined: Member Rating: 5.3
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Again, I'd like to know what term I could use for the mutation in an allele that does not change the protein it codes for ... I already told you. How does the change affect fitness? Obviously, the mutation makes no change in fitness. It is called neutral. That's all there is. I am not aware of any specific technical name for the concept "mutation that does not change protein" except "neutral." Sorry, I forgot the second part of your post. Are mutations that do not change proteins the most common type? Neutral mutations are the most common type. What percentage of these involve protein changes or not, or happen in non-coding regions or do change phenotype with no affect on fitness, I don't think anyone knows. Edited by AZPaul3, : No reason given.
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AZPaul3 Member Posts: 8513 From: Phoenix Joined: Member Rating: 5.3
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There is an observed change in the phenotype but no change in fitness, is that what you are saying? That is one type of neutral mutation, yes. Another is the one you are on about: mutation of an allele without the protein change. (I think JonF has it. Silent Mutation would be a good term for this one.)
I am not aware of any specific technical name for the concept "mutation that does not change protein" except "neutral." Which is exactly how I was using the term which caused all this brouhaha for no purpose apparently. But "neutral" mutations involve many other types as well. And your statement that
quote: is the crux of all this part of the discussion. Recognize that "neutral" refers to affect on fitness regardless of where the mutations occur or what form they take.
But obviously if there is no change in phenotype you are looking at the DNA and calling mutations at that level "neutral" but how can they be "neutral with respect to fitness" if you see no change in the phenotype anyway? You are right. If the mutation(s) cause no change in phenotype then there cannot be any change in fitness ... sooo ... those mutations are called "neutral". Faith, it does not matter if the mutation(s) change the allele but not the protein, change the protein but not the phenotype or change the phenotype ... if the mutation does not affect fitness it is termed "neutral". Yes, any mutation that does not change the phenotype can have no affect on fitness. Yes, it falls in the neutral category with all the other mutations that have no affect on fitness. Edited by AZPaul3, : No reason given. Edited by AZPaul3, : No reason given. Edited by AZPaul3, : wow, I'm bad at this today.
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