Natural Limitation to Evolutionary Processes (2/14/05)

Thanks I will check it out but I really don't have much enthusiasm for getting into the old wrangles about this stuff and following out the necessary research to keep up with evolutionists who have no respect for even the most knowledgeable creationists, and I'm no scientist. If I'm going to get involved in study it's going to be on the questions of this thread.

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That's not how it is presented on umpteen biology websites and evolution glossaries.

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Please support this claim.

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Isn't that the field known more commonly as "bioinformatics"?

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More like population genetics.

Doing a quick Google search to locate a few sources I have so far found none that insist on evolution consisting of selection without mutation:http://www.fossilmuseum.net/...m%20Scientific%20Glossary.htm http://www.stanfordalumni.org/...says/Natural_Selection.html Evolution and Natural Selection http://anthro.palomar.edu/synthetic/Default.htmhas a section on Mutation and the section on Natural Selection also mentions mutation as the source of an allele used in an example

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The only question is whether mutation increases genetic diversity enough to keep the theory of evolution afloat.

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Your thinking on this entire issue is backwards. The question isn't whether mutation can increase genetic diversity enough to counteract the other forces acting in evolution. It isn't the question because the rate of the other forces depends on how much mutation is occurring. If there is a very low mutation rate in some organism, then there will be very little new variation introduced. Little variation means that selection will act only very rarely, and that little drift will occur. Bottlenecks in such an organism's population will remove little diversity, because there wasn't much there to start with. It makes no sense to ask whether in theory mutation can keep up with these processes, since it's mutation that drives them.What would be a meaningful question is this: is the amount of genetic variation we see consistent with what we would expect if mutation were the only source of variation, and given what we know about genetic drift (which is a great deal) and about selection (not so great). Or is there too much variation, which might be the case if large populations of organisms had recently been created de novo, or too little variation, which would be the case if the Flood was a historical event. This is an experimental question, and the answer is that the amount of variation is indeed just about what we would expect if it all comes from mutation.

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Isn't the Hardy-Weinberg Equilibrium equation often used as an indicator that evolution is happening? You can compare allelic frequencies from the equation to actual allelic frequencies in the population to show that/if evolution is happening.

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I've seen HW equilibrium talked about as a test of evolution, but it is very rarely a useful one; it's just not sensitive enough, nor is it specific as to the cause of disequilibrium, even if you can detect it. The idea is that you can test whether individuals with two copies of an allele are favored by testing whether there are more of them in the population than you would expect from the allele frequency. This will work in the case of strong balancing selection, in which case you will find more heterozygotes (one copy of each allele) than you expect; I think you can detect selection acting on the sickle cell allele this way. (One copy of the allele protects you from malaria, but two copies gives you sickle cell anemia.)In general, however, you need to look at very large sample sizes in order to detect the slight shifts in genotype frequencies that you get even in pretty strong selection. And once you have sample sizes that large, you're more likely to be detecting subtle substructure in the population or assortative mating than you are selection.HW equilibrium testing is widely used in human genetics for something else, however: it's a test of genotyping accuracy, i.e. it's a check for experimental error. If everyone in your sample tests as having one copy of each allele, there's something wrong with your test.

It's not a matter of anybody insisting anything and I didn't spend a lot of time on the research. Googled "population genetics" and got a few things. I dug up some biology class outlines and evolution outlines and glossaries and they simply list the Processes of Evolution and define them without mentioning that mutation is assumed prior to any other process. I was only looking for the most basic definitions. I didn't run across the one you give: "Darwinian evolution: Evolution by the process of natural selection acting on random variation" -- found only the one about change in gene frequencies over time, which I thought was standard. Funny there are so many definitions. I got some of it off talkorigins.

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The only question is whether mutation increases genetic diversity enough to keep the theory of evolution afloat.

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Your thinking on this entire issue is backwards. The question isn't whether mutation can increase genetic diversity enough to counteract the other forces acting in evolution. It isn't the question because the rate of the other forces depends on how much mutation is occurring. If there is a very low mutation rate in some organism, then there will be very little new variation introduced. Little variation means that selection will act only very rarely, and that little drift will occur. Bottlenecks in such an organism's population will remove little diversity, because there wasn't much there to start with. It makes no sense to ask whether in theory mutation can keep up with these processes, since it's mutation that drives them.

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What would be a meaningful question is this: is the amount of genetic variation we see consistent with what we would expect if mutation were the only source of variation, and given what we know about genetic drift (which is a great deal) and about selection (not so great). Or is there too much variation, which might be the case if large populations of organisms had recently been created de novo, or too little variation, which would be the case if the Flood was a historical event. This is an experimental question, and the answer is that the amount of variation is indeed just about what we would expect if it all comes from mutation.

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As I've asked before, is there simply no more idea in anyone's mind at all of a BUILT-IN set of genetic variables that combine in sexual selection and define a species, and upon which all the selective processes work? It's ALL mutation?Flood theory assumes an enormous pre-existing built-in set of genetic variables, allowing for the destruction of the vast majority of all living things while leaving enough genetic richness to propagate everything now living. The pre-Flood world is pictured as so fecund it makes the world since appear desert-like.Is there any chance that what is called "junk DNA" or the 97% of the genome that is apparently useless, represents the destruction of the pre-Flood world in the Flood? If selection events are recorded in the genome I would expect that one to be.

Guess what. A number of people here actually go out to find the best that the creationists have to offer (not all, some don't like supporting them by buying their books). We would, of course, welcome the most knowledgable here.However, we can't find any that show much knowledge of the subjects they attack. Perhaps you can find the writtings of the "most knowledgeable creationists". That would be helpful indeed.As for respect, that has to be earned. Show us someone who has earned it.

Hey faith, I see you are still sticking to your use of the term "Processes of Evolution": I asked before and didn't get an answer. What are the Processes of Evolution? Would you please simply list them?

In the focus on mutation I've noticed that the meiotic recombination has only been mentioned a little. It is a source of genetype variation of course. However, over the long term new alleles aren't introduced that way. I think you started focussing on the very long term which is why the mutations became focussed on.

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Here is my scenario:
I have a population of 1 million individuals. This is the carrying capacity of the available resources.

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These animals live 5 years producing two surviving pups per female per year from the end of their first year.

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They have 30,000 genes. There is no junk DNA. There are therefore 30,000 alleles in the whole population.

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Each individual has 10 mutations randomly scattered in it's genes.

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Half of these are fatal and the pups carrying them are still born or not even carried to term. This gives 5 mutations per individual.
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Now what I need to do is figure out what the equilibrium diversity will be.

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This isn't exactly your scenario, but it's pretty close:Population of 1 million, with a generation time of 5 years. Each female produces a random (i.e. Poisson) number of offspring that live to reproduce, with a mean of two. (Treating the number as Poisson is a simplicification of your scenario, in which the number is capped at ten and has some granularity.) The effective mutation rate is 5 per diploid genome per generation, or 2.5 per haploid genome.For this scenario, and if we assume a very large genome, such that we can ignore multiple mutations occurring in the same base, then at equilibrium the mean number of differences between any two chromosomes is 4Nu, where N is the (effective) population size and u is the mutation rate. For your parameters this is ten million, i.e. if you compare two random chromosomes from the population they will have ten million differences. The total number of variants in the entire population is (on average) 4Nu x sum(1/i), where the sum runs from 1 to N-1; this is approximately 4Nu(ln(N) + 0.577) for large N, or 144 million.You won't get to equilibrium any time soon, however. The characteristic time here is 2N, so you'll have to wait a few tens of millions of years to be near equilibrium.(In reality, effective population sizes are usually a good deal smaller than a million, at least for the kind of organisms I'm used to dealing with. 10,000 to 100,000 is typical.)

Well, defining evolution as "change in the frequency of alleles" is hardly restricting evolution to natural selection.As to the talkorigins.org definition essay (http://www.talkorigins.org/faqs/evolution-definition.html ) it says rather moreThe Futuyama definition includes the following The author's expansion of the "change in allele frequency" definition also refers to mutation: and also states But why refer solely to the definition essay - when we have a more complete treatment expressly labelled as an "Introduction to Evolutionary Biology" ? http://www.talkorigins.org/faqs/faq-intro-to-biology.html It's even first in the list of evolution FAQs (The Talk.Origins Archive: Evolution FAQs )There we find: and: Well I can certainly believe that you didn't do much research. But if you hadn't why claim to be familiar with "umpteen" sources ?

Thanks, that is the kind of stuff I figured was out there. Still simple but we don't want to write a book on the topic.Faith can now supply the calculations that show that the loss of variance is a problem. Or maybe that isn't an issue any more? Have we finished with the topic of this thread now?

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Well, defining evolution as "change in the frequency of alleles" is hardly restricting evolution to natural selection.

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I didn't say it did.Yes, Ned, this thread is over.I get what you guys think and know where to go from here. Thank you very much.