A barrier to macroevolution & objections to it

Hi Faith!I’ve read through most of your contributions in this thread but I don’t see what you are saying?! What is it exactly that makes mutations a non likely candidate as a positive contributor to the gene pole? I’ve seen you are referring to forces of conservation and I believe something like diffusion of genetic coherency across generations as arguments against mutation.Could you please state what that force of conservation is and how it works? I know of many mechanisms that limit deviation in the gene syntax but non that single handedly or combined eradicate deviation altogether. Look for example on the mutation that gives raise to sickle cell anemia in humans, a mutation that is semi lethal, but still can proliferate and become dominant in regions where it’s favoured by selection.As to diffusion, or reblending(?), I’d like to know how you imagine that mechanism to work as to inhibit proliferation of mutation but not to make the whole genome an unintelligible DNA soup. Edited by jerker77, : No reason given.

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/jerker

There are actually contemporary observable bottle-neck situations within the human species, though not due to speciation but to isolation. We have the example of Pitcairn Island where the decedents of the Bounty mutineers have lived for 216 years in more or less splendid isolation. The original population in 1790 was 27, today they are 47 (due to emigration) but the population have in periods been up over 200. So here we have a bottleneck situation where a much limited population and thus a small generic material can be interbred for well over 200 years without the limited genetic variation doing great harm.There are of cause other examples but Pitcairn is one of the most well documented where the pedigree has been kept minutely clean. But other examples such as Iceland that were colonized in the 900 century by a small group of Norsemen and have had very little immigration are another.Though, more important is to realise that speciation, under natural circumstances, isn’t an instantaneous event but at process that takes tens of thousands of years to occur. If two species branch of from a common ancestor this mean that the interbreeding between them are dwindling over time until it come to a stop, not that it stops right when mutation X first occur.

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/jerker

I don’t think anyone would dispute the fact that inbreeding increases the incidence of harmful alleles expressing themselves. Well, that remains to be demonstrated.
200years are for humans a rather short period, given our slow reproductive rate. If we count with a short turnaround in generation 200years mean at most 10generation, i.e. 10 meiotic divisions where new mutations can occur. But if we take the Amish and the Pitcairn populations as examples we should and would expect an increased level of common hereditary traits within those communities compared to the population at large. Some of these traits will be harmful some neutral and others might even be beneficial.But is the situation of any of these two populations so bad that we should label them “endangered species”? When would you predict they will go extinct due to genetic depletion?Now let’s return to Iceland, that started out much like the Pitcairn settlement (but 1100 years ago instead of merely 200), and in the meantime have been decimated by both bubonic plague and natural disasters. It today holds a population around 230 000, it is not heavily afflicted by hereditary disorders but yes, the genetic diversity is less on Iceland than it is on the mainland.
But no one in their right mind would come up with the idea that Icelanders are a dying breed.
So how small and how long can this inbreeding take place? Pitcairn and Amish is still here after 200 years and Icelanders are here after 1100.

I don’t think speciation tendencies per se have to affect allele diversity in a drastic manner. Speciation, taken at face value, is merely the process by which two groups of organisms that used to have successful DNA swapping become are less successful till the point where coitus is no more than a waste of energy from a reproductive point of view. All that it takes is a change of the size of sexual organs or a change in breeding season. But I see your point.Though, even if you were right and mutation is to no avail, speciation is itself possible, but without mutation you could certainly not be able to take it as far present day ToE supposes.The negation of mutation does however not rule out a natural process or even make it less likely. We would still have to consider the option of hybridization and the question if the majority of the DNA, which is unused junk molecules, could in some way come into play

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/jerker

My point? I think it goes something like this: If formation of new species means a depletion of genetic variance and a lack of the same is such a bad thing that mutation is a requirement to allow for new species to survive bottlenecks, then a lack of variance in general must be equally catastrophic. Well, it isn’t!
Yes, in some cases genetic depletion can mean end of a population (or an entire species), but not likely due to semilethal or lethal alleles but due to the lack of variance to counter natural selection.The case can just not be made that mutations (apart from the standard random recombination in meiotic division) are a requirement for speciation. We could, I believe, do without them in theory.My personal opinion is that mutations play a role, bur not because they are indispensable in speciation but because they are so common.

Indeed, blessed are the meek for they shall inherit the earth!
To bad both the people in this forum and the scientific community at large are blind by Faith’s reason. But apart from that I’m most keen to see those evidences reposted (feel free to cut and past!).I have seen assumptions, one being that mutations can’t play a role in creating new alleles. But I have not seen a single study that lends it support to that theory. Neither have I seen a realistic suggestion as to how to test the assumption! But I have seen referrals to studies in bacteria that prove the contrary being discarded on the unclear assumption that much of the same stuff can’t evolve as little of the same stuff can. This being a novel idea would need to be clarified in extenso! There have also been referrals to studies in humans where new alleles have been observed forming by means of mutation. They have sadly been left without comment.I’ve also seen the assumption that bottlenecks are a dead end. A species that suffers from inbreeding is chosen, not because it is representative for organisms in bottleneck situations but because it has gene related problems and voila: “irrefutable evidence” is produced! To simply refer to one organism that suffer from, by other things, inbreeding and attribute ones ad hoc explanation is nothing near having even a testable hypothesis, let alone a proof This is particularly so since there are plenty of factual examples that bottlenecks don’t represent dead ends.I have little hope of settling this debate with arguments from observation or merely logical reasoning, since faith first and last is faith (the meaning of a statement is it’s verification). But I would like to as faith this final question:Can you think of an experiment, not a theoretic but a conductible, that can falsify, i.e. prove wrong, the account of Genesis? If the answer is yes I would like to hear it, if the answer is no . well then things are as they ought. Edited by jerker77atwork, : No reason given.

I'd like to keep jerker77, the last two are are a temporary solution since I'am at work and forgott my password, feel free to delete them! But I'd appreciate if the post could be left

Bonum est!
(it's ok)

Now, I’m a theologian not a biologist but what I can make out of the abstract of the study is this. (A person more familiar with the field might need to correct me on some or all points).The cod have been subject to a radical decimation in population due to environmental factors. The research team have looked on how this expresses itself on the gene level, using a technique where a fixed piece of DNA can be isolated and analysed across generations. They have used preserved cods available from an institute (a cod genetic library if one so like) and fresh cod from the sea. The result was as all can se first a drop in the number of alleles and then a rise. They conclude that this pattern is compatible with gene drift (a sort of mutation) and migration. They don’t think that the cod well be well of.
Plain enough? Even if you aren’t willing to discuss the matter you have just conceded to the thing you once set out to disprove and made an oxymoron in the process. I do hope God doesn’t read those lines because he would certainly not like it! You see, if mutations create new alleles the diversity is per definition increased. That is, if diversity is increased new alleles must have been formed. The thing depleted are restocked, for as you yourself have boldly stated, “I'm sure mutations create new alleles”, and something new is something that was not here before and if it wasn’t here before but is here now we now have more and if we have more we have less depletion. But of cause this might just be an inferred hypothetical speculative assumption on my part. After all, how often does 1+1=2?

Indeed!?Faith’s initial post: and talks about You’ll have to forgive a poor sinner his lack of understanding but what I was getting at was your initial statement (The first law of Faith) that the process of evolution can only work in one way and that is to reduce genetic diversity. I can only commend you in acknowledging that “You want to call mutations "alleles," so fine, they are different base code sequences so I guess they are "alleles,"”. But I liked the formulation “that mutation makes new alleles has been acknowledged all along” better. It had more of a punch! To bad it somewhat makes the resting on the seventh day hang under a doubtful scale.As for the cod I did in fact answer your questions in my, I admit, childlike rephrasing. I didn’t answer the questions one by one though so here it comes if you like it or not “a technique where a fixed piece of DNA can be isolated and analysed across generations” As said before “a piece of” and a piece is a piece is a piece. They didn’t tell so I couldn’t tell but enough for making up some alleles. They didn’t tell so I could not tell. “preserved cods available from an institute (a cod genetic library if one so like) and fresh cod from the sea” “They conclude that this pattern is compatible with gene drift (a sort of mutation) and migration.” The key word here is MIGRATION. “The result was as all can se first a drop in the number of alleles and then a rise.” So new genotypes of cause! New phenotypes were observed but the study didn’t aim to establish a relation between the specific new alleles (or loss of an old one) and the specific change in phenotype. The sentence you are referring to are however only about genotype. Of cause it means what it says! A statement is it’s verification! It says that a mutation on nonsense DNA often is related to mutation in sensible DNA that lies close to it. Given that mutations are generally a bad thing (can cause decease you know). This can hamper the recovery of the cod.And so for something completely different! You said that So what would you then call the heterozygote mutation with sickle cell anaemia that causes immunity to malaria or the two base pair deletion in the CCR5 gene that causes resistance to HIV? Are they beneficial or not?

It’s a god thing that you now concede not only to the fact that mutations enrich the gene pool, but they also, as in HIV resistance and malaria resistance in humans, can be beneficial. All what remains of your argument is then what you called “inference, speculations, assumptions and hypotheticals” The assumption being that the speed of depletion and the speed of beneficial mutations are not equal. The examples you have are taken from conservationists and breeders.The problem with that whole train of thought is of cause partly that no one would argue against genetic depletion being a problem in organisms breed under those circumstances or that certain species whose habitat have undergone rapid change are not adapted. These are things biologists and geneticists have pointed at for decades. As a matter of fact this is the prediction you will get from ToE. ToE supposes gradual diversification of the genome. The fact that dinosaurs’ went extinct is attributed to too rapid change. The facts that certain species today are going extinct are believed to be due to too rapid environmental change. The fact that certain breeding programs are resulting in depletion are the result of too rapid change. The problem will disappear as soon as there is a proximate equilibrium between the pace of genome and environment mutation. Edited by jerker77, : No reason given.

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/Jerker

Mutation isn’t wanted it’s factual, as you yourself have asserted. Indeed I believe you said that it even could be beneficial, though not beneficial enough. But then again you take a giant leap backwards when you state that the super gene is responsible for “all the microevolution” which of cause leaves no room for mutation whatsoever.As for the super-gene it is ridiculous beyond compare! Imagine that you have a human and you stuff all the genetic variety of the entire human race in this man. What du you imagine you would get? A person afflicted with every single hereditary decease, every deformity, every skin colour, every nose form, every blueprint for length, every blueprint for protein synthesis. There would most likely not be a single cell in that body that could manage to perform its first division. Alleles are not only either or’s in a strict hierarchy of dominant and recessive. They are as well both and’s and mutually exclusive’s.That not accounted for all life would hasten to it’s end since meiotic drive would sooner or later make every single species a homozygote on every single allele. Every organism would be like bacteria, just copying itself! Edited by jerker77, : No reason given.

I don’t know why you are have this obsession for cod!? The study Is just an account of changes in the number of alleles in cod caught during a period over 40 years, under which the cod population had two severe drops. It's not a closed population i.e. the cods caught over time were not direct decedents and migration did occur. All it showed that has baring on our discussion was that the number of alleles can increase even if the population is dwindling. It doesn’t prove, nor even attempt doing so, that the new alleles were beneficial nor that they were a result of mutation, though they deem mutation as a likely candidate for some of the changes in the allele counts. That's all! The point the author tries to make is that the cods genome is stressed i.e. the rapid changing environment has had a damaging effect on the cods survivability, as with the cheetah and the dog.Edited by jerker77, : No reason given.Edited by jerker77, : No reason given.