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Author | Topic: Y.E.C. Model: Was there rapid evolution and speciation post flood? | |||||||||||||||||||||||||||||||||
bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Percy writes: This is better for your scenario because now people have to demonstrate at least five alleles for a gene before they can claim any arose through mutation, and then they still have to show they produced new function. In the MHC, there are plenty of examples of more than five in small samples, like 100 individuals. There can be more than five at a 5% rate or more in the sample. That's impossible from Adam and Eve in 300 generations by drift alone. It requires positive selection of novelty, and it is Faith (although she doesn't realise it) who needs new function and positive selection for her model.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Percy writes: I agree, but I think more argument and clarification is needed for your position. Why is a (restating) "5% rate of occurrence or more in the sample for at least five MHC alleles" impossible in 300 generations by drift alone? Here's a group of 120 Cubans and 1 MHC gene. Table 1 HLA-A, allele frequencies inCuban individuals with a dengue 2 virus infection history. HLA GF (%)A*02- 22.7 A*30- 10.6 A*24- 9.5 A*68- 8.0 A*03- 7.0 A*29- 6.5 A*23- 5.5 A*01- 5.5 A*31- 4.5 A*74- 3.5 A*33- 3.0 A*32- 2.5 A*34- 2.0 A*36- 2.0 A*25- 1.5 A*26- 1.5 A*66- 1.5 A*11- 1.0 A*80- 1.0 HLA human leukocyte antigen; GF allele frequency (as percentage The easiest way to explain this might be to look at ourselves as individuals. On the YEC model, we are ~15,000 mutations away from Adam and Eve on the whole genome. That would give us ~ 180 mutational hits on the small part that is coding genes, most of them falling on different genes, so we have new alleles on ~1% of the total of ~18,000. So, if we take 120 people as above, what would we expect on a given gene in purely neutral evolution. The four original alleles dominating, and perhaps 1, 2 or 3 exceptions. Now look at the chart, and what do we see? If the YEC model, then signals of very strong selection on lots of new alleles.
Percy writes: I was browsing through the Wikipedia article on Major histocompatibility complex and see some of what you've said, for instance (going from memory) that some genes of the MHC complex have nearly 1000 alleles or more. A simple question is how so many alleles could have arisen and spread through a population in only 300 generations. Which you may have asked at least once already? With a population this size, if 1000 alleles can be tolerated, they'll be there. 100 million births gives you all the point mutations and more. So, it depends on the size of the group you're looking at. Edited by bluegenes, : nothing of note Edited by bluegenes, : removed mistake in chart
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Faith writes: I don't see what selection or drift or even number of generations has to do with any of this. I guess I'm just not getting your whole frame of reference. See if Message 66 makes it any clearer to you. Particularly, concentrate on the point that we would only have mutations (new alleles) on ~1% of our coding genes as individuals. The rest would be identical to the four in Adam and Eve. So, take a random gene and examine it on 100 people, and you'd expect the original 4 alleles + perhaps 1 individual with a new one on average.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Basically, if we all differ from Adam and Eve on just 1% of our coding genes, then take one gene, examine it in 100 people, they should mostly have the original 4 alleles, but we might expect 1 or 2 exceptions.
So, if we see something completely different, then, as serious YEC scientists, we need an explanation. For the HLA genes, very strong positive selection is the only one! This, I love. At first sight, it seems to pose serious theological problems. The new mutant alleles are taking over from the original designs. However, I can think of a way around that. It's actually diversity itself which is being selected for in the immune system. Is it plausible that the MHCs that we see in mammals could arise in a young earth scenario? Actually, no, but I'm giving it a good try. With other things, like the Y-chromosome, it's not worth bothering. Not only Noah, but Adam as well gets himself easily falsified. I'll try to bring some animals and their Ark bottleneck into the discussion.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Faith writes: But you think we NEED mutations to get new alleles and I don't, so how many there are on a gene doesn't tell me much; all I can say is the fewer the better. ???What PaulK asked above. And as for the fewer the better, didn't you understand that paper on the MHC i showed you?
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Faith writes: I gave an answer to that paper, that's all I know. ABE: You claim different functions for all those alleles, but haven't shown it. As I suggested they could all be neutral mutations that don't change the function but continue to do what the original allele did. Variety itself makes the immune system stronger. But that's not the point. They cannot be there in such high percentages in a young earth scenario unless they are positively selected. And they are there. So, what's your conclusion? Positive selection, or older earth, older life?
It has to be one or the other.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Faith writes: Mutations are random accidents of replication, yes? Most of them are neutral as to function, right:? That is, the mutated allele continues to do what the original allele did, right?: That being the case why should there be any selection involved at all? The immune system from what you've said appears to be particularly prone to mutations. No. It's no more prone than anywhere else.
Faith writes: Why should there be any other reason for that than its proneness to frequent random accidents of replication to explain the rate at which they occur? It isn't prone to these, and the alleles that are present as a measurable percentage are certainly highly functional, otherwise they would be selected out quickly. They face positive selection because two different ones working in tandem is better than an identical pair. There's no explanation for their survival other than positive selection. They are like soldiers with slightly different arms.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Faith writes: They can be functional simply by not doing anything different than the original allele did, which is what "neutral" mutations do. Yes, but they (new human immune system alleles) wouldn't be present in the proportions that they are after 300 generations on neutral evolution alone. Only positive selection on new variants would give that effect. That's why I'm saying that, to get a plausible 6,500yr YEC model, we have to accept positive selection on many of those extra HLA alleles. It will be the same for other animals after the Ark bottleneck, particularly those species (or kinds) that only had two members present. When we look at them now, lots of variants in the MHC will be present at proportions that are too high for neutral evolution (drift) to account for, as they could only have a maximum of 4 after the flood. So, we have to put positive selection on MHC mutant alleles as part of any plausible YEC model. If, like the folk at Answers in Genesis, you see "kind" at somewhere around the level of family, you will need positive selection during post flood speciation and niche filling as well, even if you argue that the genes/alleles were all present on the original Ark pair genomes.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
NosyNed writes: So the remaining question is:Are the mutations neutral or beneficial? If they are neutral they are, by definition, not selected for or against so they only spread through the population by random drift. So the issue of whether there are any beneficial mutations can be settled by examining if there are any alleles other than the original handful that are spread more widely than drift can do in a few 1,000 years. As I understand the discussion so far the answer to that is - yes. Therefore the conclusion is that the human genome has acquired beneficial mutations since the flood or the flood was much longer ago than a few 1,000 years. That's pretty much it, but not just the flood, Adam and Eve as well.
NNed writes: If there have been beneficial mutations then the original genome was not "perfect". Well, there's a twist to that so far as the HLA alleles are concerned. Adam and Eve, like everyone else, would have had two copies at each locus, and if they had two different complimentary variants on each HLA gene, then they are as perfect as possible. From then on, it's downhill at first, because with only 4 possible alleles, it's a one in three chance of someone having two of the same alleles on any given locus which, for these codominant alleles, is usually a disadvantage, because variety in immune system weaponry is the spice of life. That's where new functional mutants can help, because every added one decreases the chances of a matching pair. So, it is not that the new alleles are more perfect than the original. Variety itself is facing positive selection, so the YECs needn't necessarily have a theological objection to this.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined:
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Faith writes: Adam and Eve had the genes to produce every skin color there is. Depending on how many children they had they could have produced the entire range in one generation, but certainly produced quite a large range of them in any case. The rest would have appeared in subsequent generations. And 80 generations later, all the original diversity was still present in Noah's sons and their wives?
Faith writes: What makes a skin color or any other trait characteristic of a population or race is some form of selection of the color or few colors, and the selection as I've been arguing is in most cases random, a matter of migration of individuals that possess a particular portion of the gene pool ending up as an isolated population in some new place, where they develop a characteristic skin color through generations of inbreeding. That's all it takes for there to be hundreds of different populatios with different characteristics. It's all in the original genome, brought to visible expression by random seleciton and reproductive isolation. By "random selection" do you mean drift (neutral evolution-no selection involved)?
Faith writes: And each new race or population develops its characteristic traits by LOSING all the genetic material for other traits, many of which become characteristic of other populations. The original genome for each Kind had tremendous genetic diversity that in various combinations produced all the separate populations or "species" of all Kinds, but each new species has its characteristic phenotypes as a result of losing the genetic material for all the others. So the ancestral bear kind on the Ark would have contained all the genes/alleles necessary to make a polar bear and a panda? Even if so, surely natural selection on these would be necessary to produce things like the Arctic adaptations of the Polar? Research on 59 Alpine Chamois found 19 alleles on one locus, and this level of polymorphism is turning out to be widespread, so I think you have to bring mutation and positive selection into your model, because mutation + drift from an Ark bottleneck doesn't fit what we see.
Evolution defeats Evolution. We shall see! I think YECs need to become super-selectionists in order to fit the genetics and the niche adaptations within kinds.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
jar writes: bluegenes writes: Well, there's a twist to that so far as the HLA alleles are concerned. Adam and Eve, like everyone else, would have had two copies at each locus, and if they had two different complimentary variants on each HLA gene, then they are as perfect as possible. But Eve was a clone of Adam so would that be possible? Yes, they're diploid. They could be the same as each other and still have two different variants on each gene. However, if they were clones, that's not very good design from the point of view of their descendants. I don't see why you can't make any genes out of a rib if you can from dirt, anyway.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Tangle writes: I assume on 'kind' would be marsupial? No. Some YECs go as far as family, but certainly not class or sub-class. So kangaroos and wallabies might be lumped, but not marsupials. If someone's mentioned class on this thread, it'll be a typo! It has partly to do with hybrids being possible, partly to do with limited space on the Ark, and partly a reaction to genetics and directly observable adaptations/evolution, I think. Anyway, species immutability is out (unless you're in the Davidjay camp), but "kind" or family immutability is definitely still in.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
jar writes: Yet we know for a fact that everyone has a different set of genes which is why DNA testing can identify a specific individual. Coding genes (~1% of DNA) aren't any use for that. It's the "junk" that mutates quickly without restraint, like micro-satellites, that gets used because it's highly variant. It's also used for approximate dating, and shows that many "kinds" split into species a long, long time before the Ark. The earliest splits in the giraffe kind, for example, come in at over 1 million years, and far more if we include the Okapi.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Percy writes: What Faith is saying is that everyone has the same genes but with potentially a variety of different alleles, and that the current alleles are the only ones that aren't deleterious. Any mutations in existing alleles would be deleterious. I don't think so. Her posts here certainly seem to accept "neutral". But I'm sure she'll clarify.
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bluegenes Member (Idle past 2506 days) Posts: 3119 From: U.K. Joined: |
Faith writes: bluegenes writes: That's why I'm saying that, to get a plausible 6,500yr YEC model, we have to accept positive selection on many of those extra HLA alleles. Well, I'm just a creationist loony but I would guess there are many variables here you probably haven't taken into account, and if I can't derive your statistic myself I can't very well accept it anyway. Drift can increase and decrease the frequency of alleles (the percentage of the population in which they are present) but it certainly can't explain what we see with the HLA alleles. Perhaps it would be easier to explain directly how the new alleles are advantageous, and how they are necessarily different in how they function.
MHC polymorphism extends the range of antigens to which the immune system can respond. quote: *"The extensive polymorphism of the MHC proteins has almost certainly evolved to outflank the evasive strategies of pathogens. That should make sense to you (post Fall).
**"That exposure to pathogens over an evolutionary timescale can select for expression of particular MHC alleles is indicated by the strong association of the HLA-B53 allele with recovery from a potentially lethal form of malaria; this allele is very common in people from West Africa, where malaria is endemic, and rare elsewhere, where lethal malaria is uncommon." Undeniable natural selection, surely. Bear in mind that there are several of these very polymorphous genes, and that if the Adam & Eve maximum of 4 alleles was all that was available to us, then homozygousity would be common (1/4 of the population on each gene, and most people on at least one). Note also the first sentence in yellow. The new alleles are significantly different, and do not arrive easily by a single point mutation. So, these new arrivals being different is important, and they are certainly beneficial. Therefore, I repeat the title of the sub-thread:
The YEC model requires beneficial mutations and strong positive selection. I think you'll agree if you understand the information in the paper.
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