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Author | Topic: How novel features evolve #2 | |||||||||||||||||||||||||||||||||||||||||||
herebedragons Member (Idle past 888 days) Posts: 1517 From: Michigan Joined:
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So the likelihood of an entire gene being duplicated without damage to an organism is small, that's why i need proof that this was a duplication and not a deletion. When referring to humans, yes. Humans seem especially sensitive to major genetic changes. I am not sure exactly why this is or if it even has any statistical significance. It may just be that we are more aware of genetic defects and subsequent loss of fitness in humans. But humans are less than ideal genetic models. It is considered unethical to do genetic manipulations in humans. We study those defects that present phenotypic expression that causes disease. We don't look for genetic "defects" when someone is healthy. So anyway, to study genetic mutations we use "model organisms" such as Drosophila, Arabidopsis, Saccharomyces and Caenorhabditis to name a few. If you review studies on these organisms you will find many duplications that increase fitness or have other useful functions to the organism.
My reason is that when you duplicate the proteins produced you normally get a less fit organism because of the excess proteins causing imbalance in the organism. The proteins required for each function are very precise and even a slight increase in protein production through insertions within a gene can decrease fitness (Huntington's disease). Major duplications of entire chromosomes cause major loss of fitness as in Down's syndrome. So the likelihood of an entire gene being duplicated without damage to an organism is small You are oversimplifying the situation. There is much more going on than just protein production. The situation is much, much more complicated than that. It involves gene interactions, not just in the duplicated genes, but with genes on other chromosomes as well. It also depends heavily on what the gene product does. Some proteins can be overexpressed with little or no effect, some cause severe problems and others provide a benefit. Such generalized statement as these really don't have any significance. Again, if you look only at the human genome, then yes, you will probably find this to be the case most of the time. But not so for other organisms. You just need to do a little research on the topic. I have already mentioned polyploidy in plants. Turns out polyploidy can be very beneficial to plants. Many of our food crops are polyploids. Here is an example of overexpression providing a benefit
quote: Without the proof that the original population was devoid of the duplicates, the whole point is meaningless. Unfortunately, science doesn't quite work this way; proof is an unrealistic goal. The best we can do is collect evidence and make the most of it. Do we need to make some assumptions? Yes. Do we make inferences? Of course. But to think those are things that hinder proper scientific investigation is just not realistic. We have to do the best we can with the information at hand. If there is evidence that contradicts the assumptions and inferences that have been made, then the conclusions will be overturned. But as long as the evidence points in a certain direction, conclusions are drawn from that.
The proteins required for each function are very precise and even a slight increase in protein production ... Then wouldn't it also be true that a decrease in protein production would decrease fitness? Whoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for. But until the end of the present exile has come and terminated this our imperfection by which "we know in part," I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca "Nothing is easier than to persuade people who want to be persuaded and already believe." - another Petrarca gem.
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Taq Member Posts: 10085 Joined: Member Rating: 5.6
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Yes, I would say unlikely ever to happen, not impossible. My reason is that when you duplicate the proteins produced you normally get a less fit organism because of the excess proteins causing imbalance in the organism. Based on what evidence? Or is it just your say so? I have just shown an example of a gene duplication increasing fitness, and still you refuse to accept it.
The proteins required for each function are very precise and even a slight increase in protein production through insertions within a gene can decrease fitness (Huntington's disease). We aren't talking about insertions within a gene. We are talking about the duplication of the entire gene. Insertions can disrupt a reading frame and cause disease, but nowhere have you shown that this happens every time. Even more, you have not shown that protein sequences or expression need to be precise. For example, the cytochrome C gene differs by 40% in sequence between humans and yeast, and yet you can replace the yeast gene with the human gene and the yeast doesn't even notice. If proteins need to be so precise then why can you change the sequence by 40% and get the same function?
Major duplications of entire chromosomes cause major loss of fitness as in Down's syndrome. They CAN cause a decrease in fitness, but there is no guarantee that they will every time. Nowhere have you shown that large duplications will always result in a decrease in fitness.
So the likelihood of an entire gene being duplicated without damage to an organism is small, that's why i need proof that this was a duplication and not a deletion. The evidence is a lack of variation between the two genes. This indicates a recent duplication. If these are not duplicates then they would have accumulated different neutral mutations over time and diverged. If the gene is the result of a recent duplication then the sequences will not have diverged much. To determine which is the case you do a phylogenetic analysis which is exactly what these authors did: "Phylogenetic analysis of nucleotide sequences indicates that both putative aphid Rdl loci are monophyletic with respect to other insect Rdl genes and may have arisen through a recent gene duplication event."Duplication of the Rdl GABA receptor subunit gene in an insecticide-resistant aphid, Myzus persicae - PubMed Of course, natural mechanisms are capable of duplicating genes. In this example we see that having a duplicate increases fitness. Therefore, natural mechanisms are capable of producing duplicate genes that increase fitness.
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Taq Member Posts: 10085 Joined: Member Rating: 5.6
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Why do you eliminate the possibility that it was a deletion that was being eliminated from the population? Because of the lack of sequence divergence between the two genes. This indicates a duplication.
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mindspawn Member (Idle past 2690 days) Posts: 1015 Joined: |
I have been trying to see your evidence that the duplicate came after the single gene, and still feel you have given no evidence of this. The lack of sequence divergence just means the genes are the same. I have never doubted you on this. You may not be able to see this, but you are basing your entire argument on the assumption that the duplicated gene was the later mutation, with no evidence put forward yet.
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Taq Member Posts: 10085 Joined: Member Rating: 5.6
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The lack of sequence divergence just means the genes are the same. Yes. If they were not the result of duplication then they would have many differences in sequence. The lack of variation between the sequences is the evidence for a recent duplication. Why do I say this? There is nothing stopping neutral mutations from accumulating in these genes. It is entirely possible to change the nucleotide sequence without change the protein sequence due to third base wobble (i.e. some amino acids are coded for by more than one codon). Therefore, if these genes had existed for quite some time as separate copies then they would have different a lot of different neutral mutations. They don't. Therefore, the evidence is strongly in favor of a recent duplication.
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mindspawn Member (Idle past 2690 days) Posts: 1015 Joined: |
Post deleted, due to duplication. The duplication followed the original in this case .....lol
Edited by mindspawn, : Duplicate post
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mindspawn Member (Idle past 2690 days) Posts: 1015 Joined: |
"Yes. If they were not the result of duplication then they would have many differences in sequence. The lack of variation between the sequences is the evidence for a recent duplication"
I believe its possible God created the original with two identical genes. This original with the two genes is the stronger of the two varieties, and therefore survived the pesticides. I see nothing in your evidence that says the population without the duplicate came before the population with the duplicate, except your presumption that evolution is more logical than intelligent design. If you can show me proof that the population without the duplicate was on earth first, you would have a point. Otherwise you are trying to prove a process of evolution based on the assumption that the duplicate evolved which is frankly illogical. Edited by mindspawn, : No reason given.
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Taq Member Posts: 10085 Joined: Member Rating: 5.6
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I believe its possible God created the original with two identical genes. What evidence do you have that a supernatural deity created any species? Surely you demand as much evidence for creationism as you do for evolution, right?
I see nothing in your evidence that says the population without the duplicate came before the population with the duplicate, except your presumption that evolution is more logical than intelligent design. It would appear that your beliefs you discussed above are preventing you from accepting the evidence that I have presented. I'm sorry, but "I believe . . " is not a valid reason for rejecting evidence.
If you can show me proof that the population without the duplicate was on earth first, you would have a point. Otherwise you are trying to prove a process of evolution based on the assumption that the duplicate evolved which is frankly illogical. Why is it illogical?
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Percy Member Posts: 22506 From: New Hampshire Joined: Member Rating: 5.4
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Hi MindSpawn,
You replied to Taq as if you hadn't understood a thing he said, but I'll let Taq address that. I'm only writing because now that you've been here a whole 4 days it's time to start using the quoting codes instead of just quotes. Here's where you quote Taq using only quotes:
"Yes. If they were not the result of duplication then they would have many differences in sequence. The lack of variation between the sequences is the evidence for a recent duplication" I believe its possible God created the original with two identical genes. This original with the two genes is the stronger of the two varieties, and therefore survived the pesticides. But you could have done it like this:
Taq writes: "Yes. If they were not the result of duplication then they would have many differences in sequence. The lack of variation between the sequences is the evidence for a recent duplication" I believe its possible God created the original with two identical genes. This original with the two genes is the stronger of the two varieties, and therefore survived the pesticides. The way you do this is with quoting codes. I did it like this:
[qs=Taq]"Yes. If they were not the result of duplication then they would have many differences in sequence. The lack of variation between the sequences is the evidence for a recent duplication"[/qs] I believe its possible God created the original with two identical genes. This original with the two genes is the stronger of the two varieties, and therefore survived the pesticides. Anything you want to quote just put a [qs] at the front and a [/qs] at the rear. There are a lot other codes for a variety of things like images, fonts, colors, formatting, etc. If you want to see how anybody created their message just click on the "peek" button that appears at the bottom right of their message. Or you can read the dBCode Help. --Percy Edited by Percy, : Fix typo.
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mindspawn Member (Idle past 2690 days) Posts: 1015 Joined: |
Thanks Percy , appreciated
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mindspawn Member (Idle past 2690 days) Posts: 1015 Joined: |
What evidence do you have that a supernatural deity created any species? Surely you demand as much evidence for creationism as you do for evolution, right? I haven't got evidence , except that the bible is a proven and accurate book, which is of topic for this thread. Neither have you got evidence for your evolutionary process because you are using the assumption of evolution to prove evolution. You are not taking into account the possibility of ID, which gives an alternative possibility that the duplicate came first.
It would appear that your beliefs you discussed above are preventing you from accepting the evidence that I have presented. I'm sorry, but "I believe . . " is not a valid reason for rejecting evidence Percy is right that I didn't respond to your one point. You say that these two genes have few differing neutral mutations. This is often another point of contention between ID's and evolutionists. To what extent are these neutral mutations truly neutral, when some so-called "junk-DNA" has recently been found to have a function. ie if organisms are not collecting neutral mutations , but those so-called neutral mutations have always had a specific function and are a core part of the DNA, then this would mean there is far more stability in the DNA than you predict. This stability would explain the lack of diversity between the two genes over long periods of time.
Functions of Junk DNA
Edited by mindspawn, : No reason given. Edited by mindspawn, : trying to learn how to quote Edited by mindspawn, : getting quotes right Edited by mindspawn, : correcting my post
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NoNukes Inactive Member
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You are not taking into account the possibility of ID, which gives an alternative possibility that the duplicate came first. Not exactly. Mutations are known to occur in humans. The absence of mutation is at least some evidence that a gene has recently appeared.
but those so-called neutral mutations have always had a specific function and are a core part of the DNA, then this would mean there is far more stability in the DNA than you predict. Having a specific function alone would not make a section of DNA resistant to change. It might mean that such changes would not be selected and would not propagate but only if the mutation does not affect your ability to sire or mother offspring. As has been already presented, you possess mutations that are not a part of your parent's genetic makeup. Everyone does. You also seem to be confusing junk DNA with functioning DNA being able to operate despite modification. Edited by NoNukes, : No reason given.Under a government which imprisons any unjustly, the true place for a just man is also in prison. Thoreau: Civil Disobedience (1846) The apathy of the people is enough to make every statue leap from its pedestal and hasten the resurrection of the dead. William Lloyd Garrison. If there is no struggle, there is no progress. Those who profess to favor freedom, and deprecate agitation, are men who want crops without plowing up the ground, they want rain without thunder and lightning. Frederick Douglass
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Theodoric Member Posts: 9202 From: Northwest, WI, USA Joined: Member Rating: 3.4 |
I haven't got evidence , except that the bible is a proven and accurate book, which is of topic for this thread. Then why are you posting to a science thread if all you have is bronze age myths? You are not going to accept any scientific evidence that goes against your "bible". You speak of this "bible" as if it is one book with consistent text. Since there really is no "bible" your claim that it is "proven and accurate" is patently false. Please read my signature.Facts don't lie or have an agenda. Facts are just facts "God did it" is not an argument. It is an excuse for intellectual laziness.
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Percy Member Posts: 22506 From: New Hampshire Joined: Member Rating: 5.4
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mindspawn writes: I haven't got evidence, except that the bible is a proven and accurate book, which is of topic for this thread. But in that case you must have at hand the evidence that proved the Bible accurate. All you need do is propose a thread to review this evidence, and once this evidence has been revealed to us you can return to this thread and cite the Bible as scientific evidence. --Percy
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Tangle Member Posts: 9516 From: UK Joined: Member Rating: 5.1
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mindspawn writes: I haven't got evidence , except that the bible is a proven and accurate book, which is of topic for this thread. You are extremely skeptical about evolution, to the extent of arguing at the genetic level against it. Can you put your hand firmly on your heart and tell us that you have applied this level of skepticism to your reading of the bible?Life, don't talk to me about life - Marvin the Paranoid Android
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