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Author Topic:   Evolutionary momentum
Mammuthus
Member (Idle past 6475 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 16 of 33 (27326)
12-19-2002 5:16 AM
Reply to: Message 14 by [xeno]Julios
12-19-2002 1:44 AM


Hi XJ
That's coz i just made it up - here's a crude analogy that might help: Think of a bowl or a basin. Now put a marble into it and swirl the bowl for a few seconds. The ball will start to roll around the sides of the basin until it settles in a stable state, most likely at the bottom of the bowl. This is because of the way gravity, and the curve of the inner surface of the basin, interact. Similarly, by mutative basin, I mean a genetic state that will arise because of mutational hotspots (the surface of the bowl), and the laws of physics and chemistry (gravity). It has absolutely nothing to do with survival consequences. Survival consequences will determine which mutations are allowed to persist, while mutative basins will determine which mutations are likely to occur in the first place!!
M: The problem in this analogy is that gravity would be selection and is the selective force that tends to make the marble travel in a specific direction. Also the curve of the bowl would be a selective force. Quetzal did a great job of pointing out the issues of mutation so I won't go into it since I agree with what he said. I would only add that the mutation rate and amount of mutations or polymorphism in a population will depend on the rate of error of the various polymerases and the size of the effective or breeding population.
cheers,
M

This message is a reply to:
 Message 14 by [xeno]Julios, posted 12-19-2002 1:44 AM [xeno]Julios has not replied

  
[xeno]Julios
Inactive Member


Message 17 of 33 (27387)
12-19-2002 2:37 PM
Reply to: Message 15 by Quetzal
12-19-2002 3:28 AM


Thanks for the response Quetzal
quote:
Originally posted by Quetzal:
XJ:
I think I'm beginning to understand what you're trying to get at here. Are you asking whether consecutive mutations at a "mutational hotspot" that might have a neutral phenotypical effect can accumulate phenotypical change over time?

Think of it in terms of a mutational pathway: each "state" along this pathway would have a different "mutational hotspot" and the series of mutational hotspots would define the "pathway". As you have indicated later on in your post, yes indeed this pathway would only pose a statistical likelihood of being "traversed"
Now - think of the entire pathway as a conceptual "basin" - the stable centre of which is simply a point of probability. Thus, there is only a higher probability of the genetic state settling in that basin, as compared to any other arbitrary state. Forget about survival pressures for now; the whole point of this thought experiment is to conceptually dissociate the environmental pressures and the ensuing survival consequences from the mutations that occur - remember, this basin would determine the statistical likelihood of a mutation actually occuring while the environment would influence which mutations "survive" and are propogated.
Now, my question in part is whether these pathways could incidentally be expressed by a gradual change in a specific phenotype. By this, let me try to illustrate: imagine a mutational pathway exists, by virtue of the successive hotspots that arise after each mutation. Now, in some cases, these very mutations will be expressed in a certain way in the organism. Sometimes each of these successive mutations will express completely unrelated "traits" - for example the first mutation would code for a protein X, and the second one would code for a completely different enzyme. Or even more abstractly, mutation A could alter the eye colour, while mutation B would influence production of haemoglobin, and mutation C would sprout an extra limb!
However, I am asking whether it is feasible to postulate pathways that express a gradual change in a specific phenotype. For example: mutation A would express itself as a longer finger, mutation B would give rise to an even longer finger. And of course if this was the case, then all things being equal (for example say this set of organisms evolved in a completely (hypothetical) neutral environment) then there would be an increased statistical likelihood that over the eons, longer fingers would become the norm.
Now back to the real world: let's say that longer fingers actually was a huge survival advantage. In this scenario, we have two independent "pressures" that direct the growth and survival of longer fingers: on the one hand, the survival advantage would facilitate an increased likelihood that longer fingered organisms would survive and reproduce more, etc... on the other hand, there is the mutative basin that guides the necessary mutations. In this case, the mutational basin would give momentum to the evolution of longer fingers.
I hope this makes sense, and I appreciate all the responses so far.
Marwan
Julios, 12-19-2002

This message is a reply to:
 Message 15 by Quetzal, posted 12-19-2002 3:28 AM Quetzal has not replied

Replies to this message:
 Message 19 by Brad McFall, posted 12-20-2002 12:40 AM [xeno]Julios has not replied
 Message 20 by Mammuthus, posted 12-20-2002 4:28 AM [xeno]Julios has replied

  
Brad McFall
Member (Idle past 5033 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 18 of 33 (27445)
12-20-2002 12:36 AM
Reply to: Message 1 by [xeno]Julios
12-16-2002 8:15 AM


Before getting down to the Q level documenting from that point and above, below. I'll bite in the general momentum of any TRAIT (lets say by that something that would have to in the controversy be referred back to Mendel +- modern genetics) If yes-->
When thinking of this I found that on reading Galelio I was thinking of something different than Newton. [This message has been edited by Brad McFall, 12-20-2002]

This message is a reply to:
 Message 1 by [xeno]Julios, posted 12-16-2002 8:15 AM [xeno]Julios has not replied

  
Brad McFall
Member (Idle past 5033 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 19 of 33 (27446)
12-20-2002 12:40 AM
Reply to: Message 17 by [xeno]Julios
12-19-2002 2:37 PM


There is not a problem with thinking spatially of a "mutation hotspot" however my guess is that this positionally CONstraints the constraining at any genetics involved to that which is subject only to synthetic chemistry of the Linus Pauling Bond. There is no reason to not do or try to do chem on this memory but there are other ways to consider the expression of genes as will become more apparent if I release some ideas about "cracking" the code.

This message is a reply to:
 Message 17 by [xeno]Julios, posted 12-19-2002 2:37 PM [xeno]Julios has not replied

  
Mammuthus
Member (Idle past 6475 days)
Posts: 3085
From: Munich, Germany
Joined: 08-09-2002


Message 20 of 33 (27457)
12-20-2002 4:28 AM
Reply to: Message 17 by [xeno]Julios
12-19-2002 2:37 PM


Now - think of the entire pathway as a conceptual "basin" - the stable centre of which is simply a point of probability. Thus, there is only a higher probability of the genetic state settling in that basin, as compared to any other arbitrary state.
M: However, this is contrary to what is expected. You would expect a normal distribution of mutations among individuals if it is a stochastic and random process and this is what is observed. Thus, you would not expect to settle in any one state.
X:
Forget about survival pressures for now; the whole point of this thought experiment is to conceptually dissociate the environmental pressures and the ensuing survival consequences from the mutations that occur - remember, this basin would determine the statistical likelihood of a mutation actually occuring while the environment would influence which mutations "survive" and are propogated.
M: Again, there is only counter evidence for such directional mutations so I don't think the basin model is viable.
Now, my question in part is whether these pathways could incidentally be expressed by a gradual change in a specific phenotype. By this, let me try to illustrate: imagine a mutational pathway exists, by virtue of the successive hotspots that arise after each mutation. Now, in some cases, these very mutations will be expressed in a certain way in the organism. Sometimes each of these successive mutations will express completely unrelated "traits" - for example the first mutation would code for a protein X, and the second one would code for a completely different enzyme. Or even more abstractly, mutation A could alter the eye colour, while mutation B would influence production of haemoglobin, and mutation C would sprout an extra limb!
M: Unfortunately, almost all of the "hotspots" are in non-coding sequences as those that do have an impact on a trait/protein are immediately selectively advantageous or disadvantegeous.
X:
However, I am asking whether it is feasible to postulate pathways that express a gradual change in a specific phenotype. For example: mutation A would express itself as a longer finger, mutation B would give rise to an even longer finger. And of course if this was the case, then all things being equal (for example say this set of organisms evolved in a completely (hypothetical) neutral environment) then there would be an increased statistical likelihood that over the eons, longer fingers would become the norm.
Now back to the real world: let's say that longer fingers actually was a huge survival advantage. In this scenario, we have two independent "pressures" that direct the growth and survival of longer fingers: on the one hand, the survival advantage would facilitate an increased likelihood that longer fingered organisms would survive and reproduce more, etc... on the other hand, there is the mutative basin that guides the necessary mutations. In this case, the mutational basin would give momentum to the evolution of longer fingers.
M: I could envisage a trait that is not selected on becoming fixed in a population by chance i.e. by genetic drift you end up with an overall averge small size in the population though larger sizes would be equally supportable. The environment changes suddenly and small size is a huge advantage and maintains the state or causes average size to decrease further. However, this is not a directional mutation. This is plain evolution. Chance mutations that in a given environment are either advantageous, neutral, or detrimental. The larger the population (the population could be seen as your mutation basin) the more possible mutations exist (since a diploid organism only has two copies of any given nuclear gene), and the more possible genotypes available on which selection can work. That is why genetic bottlenecks can really suck for a species. If you remove almost all the variation from a population, the environment changes and the given phenotype or few phenotypes are not suitable to the changed environment, then there are no individuals that may have a better phenotype that can survive to reproduce and extinction is a possible outcome.
Another scenario is that a highly selected trait is genetically linked to a completely neutral trait. The non-selected trait will get fixed in a particular state because of linkage with the selected trait. But this is not the same thing as what you are proposing because the non-selected trait is hitchhiking to fixation because of selection on a different trait.
But without selection I don't see your directed mutations happening as you envisage.
cheers,
M
[This message has been edited by Mammuthus, 12-20-2002]

This message is a reply to:
 Message 17 by [xeno]Julios, posted 12-19-2002 2:37 PM [xeno]Julios has replied

Replies to this message:
 Message 21 by [xeno]Julios, posted 12-20-2002 2:23 PM Mammuthus has not replied

  
[xeno]Julios
Inactive Member


Message 21 of 33 (27499)
12-20-2002 2:23 PM
Reply to: Message 20 by Mammuthus
12-20-2002 4:28 AM


quote:
Originally posted by Mammuthus:

However, this is contrary to what is expected. You would expect a normal distribution of mutations among individuals if it is a stochastic and random process and this is what is observed. Thus, you would not expect to settle in any one state.

In other words, such hypothetical basins probably do not exist, and most mutational pathways are indeed not basins but rather a random accumulation of genetic states.
quote:
Originally posted by Mammuthus:
Unfortunately, almost all of the "hotspots" are in non-coding sequences as those that do have an impact on a trait/protein are immediately selectively advantageous or disadvantegeous.

Ah - I didn't realize this. However, is it feasible to postulate that what we might consider non-coding sites, are actually crucial in some ways? What we might consider "junk" DNA might actually be an integral part of a bigger equation? Going back to the shape of a nose - the fact that we do not understand the epigenesis of the shape of a nose seems to indicate that we have not cracked the code of DNA. As far as I understand, what we do know about gene expression is simply the manufacturing and regulation of protein production - perhaps there are deeper layers of information hidden inside the structure of DNA, and these apparent junk spots are actually parts of this information structure - pure speculation here, but would like to hear other's thoughts...
quote:
Originally posted by Mammuthus:
I could envisage a trait that is not selected on becoming fixed in a population by chance i.e. by genetic drift you end up with an overall averge small size in the population though larger sizes would be equally supportable. The environment changes suddenly and small size is a huge advantage and maintains the state or causes average size to decrease further. However, this is not a directional mutation. This is plain evolution. Chance mutations that in a given environment are either advantageous, neutral, or detrimental. The larger the population (the population could be seen as your mutation basin) the more possible mutations exist (since a diploid organism only has two copies of any given nuclear gene), and the more possible genotypes available on which selection can work. That is why genetic bottlenecks can really suck for a species.
So this genetic drift would also be a random process, but is it not interesting that such a drift would be expressed as a gradual phenotypical change? The (non-hotspot) mutations that facilitated this drift may indeed be random but the fact that they resulted in a gradual change in a given phenotype may indicate some deeper mathematical pattern - maybe something to do with the homology of the organism.
You ever wonder at the almost supernatural quality of metaphors? The fact that one can take two seemingly independent and unrelated processes and create an analogue with them, shows that there is a mathematical pattern linking the two - for example - we talk about "waves" of fear or emotion - the analogy is between a physical wave, and the dynamics of perceived emotion - a wave starts out gradually, builds up to a crest, and propogates - the mathematical equations that govern the propogation of a wave can be applied to the dynamics of emotion. Perhaps these same sort of universal patterns underly genetic evolution, and thus give the appearance of intelligence or direction. I'm sorta groping in the dark here...
quote:
Originally posted by Mammuthus:

Another scenario is that a highly selected trait is genetically linked to a completely neutral trait. The non-selected trait will get fixed in a particular state because of linkage with the selected trait. But this is not the same thing as what you are proposing because the non-selected trait is hitchhiking to fixation because of selection on a different trait.

Yes exactly it would be hitchhiking - I guess my biggest question is how to explain gradual phenotypical changes - it doesn't jive well with my instinct to think of it as purely random - random in the sense that the mutations may occur at random (stochastically as you said) yes - but the fact that these random changes give rise to patterned growth may imply that selection alone may not account for this. This is not necessarily to say that there is intelligence governing the principles of evolution - but perhaps that there may be hidden (at least at present) patterns within DNA that allow for interesting and gradual phenotypical progressions even with a random mutative engine.
Thanks for the reply - I think you finally understood what I was getting at.
Marwan

This message is a reply to:
 Message 20 by Mammuthus, posted 12-20-2002 4:28 AM Mammuthus has not replied

Replies to this message:
 Message 22 by Brad McFall, posted 12-22-2002 12:50 AM [xeno]Julios has replied
 Message 25 by Quetzal, posted 12-23-2002 4:43 AM [xeno]Julios has replied

  
Brad McFall
Member (Idle past 5033 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 22 of 33 (27625)
12-22-2002 12:50 AM
Reply to: Message 21 by [xeno]Julios
12-20-2002 2:23 PM


There is an alternative in the concept of neo-phenogenesis for which I tend to think salamander guilds can be explained. But this idea being against Darwikins more conservative postition is hard to get across. A one, Gottlieb, put the idea out under this rubric.

This message is a reply to:
 Message 21 by [xeno]Julios, posted 12-20-2002 2:23 PM [xeno]Julios has replied

Replies to this message:
 Message 23 by [xeno]Julios, posted 12-22-2002 6:35 AM Brad McFall has replied

  
[xeno]Julios
Inactive Member


Message 23 of 33 (27636)
12-22-2002 6:35 AM
Reply to: Message 22 by Brad McFall
12-22-2002 12:50 AM


quote:
Originally posted by Brad McFall:
There is an alternative in the concept of neo-phenogenesis for which I tend to think salamander guilds can be explained. But this idea being against Darwikins more conservative postition is hard to get across. A one, Gottlieb, put the idea out under this rubric.
Can you elaborate on what exactly this means? Also, I had a lot of difficulty understanding your last two posts before this one - they weren't very coherent

This message is a reply to:
 Message 22 by Brad McFall, posted 12-22-2002 12:50 AM Brad McFall has replied

Replies to this message:
 Message 24 by Brad McFall, posted 12-23-2002 12:09 AM [xeno]Julios has replied

  
Brad McFall
Member (Idle past 5033 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 24 of 33 (27705)
12-23-2002 12:09 AM
Reply to: Message 23 by [xeno]Julios
12-22-2002 6:35 AM


Yes, but I need to "cool" down from the "holland" interaction. By "hot spot" I meant merely a short cut for my understanding of geneic balance and the whole issue of the position effect in general genetics and as for herpetology that will take some telling too. I will try to go back over all this with a fine toothed comb as soon as I dont feel like reading Einstein anymore.

This message is a reply to:
 Message 23 by [xeno]Julios, posted 12-22-2002 6:35 AM [xeno]Julios has replied

Replies to this message:
 Message 27 by [xeno]Julios, posted 12-25-2002 3:27 AM Brad McFall has replied

  
Quetzal
Member (Idle past 5872 days)
Posts: 3228
Joined: 01-09-2002


Message 25 of 33 (27716)
12-23-2002 4:43 AM
Reply to: Message 21 by [xeno]Julios
12-20-2002 2:23 PM


Hi XJ:
Mammuthus pretty much covered what I would have said in response to your next-to-last post, so I'll take a stab at this one.
quote:
Ah - I didn't realize this. However, is it feasible to postulate that what we might consider non-coding sites, are actually crucial in some ways? What we might consider "junk" DNA might actually be an integral part of a bigger equation? Going back to the shape of a nose - the fact that we do not understand the epigenesis of the shape of a nose seems to indicate that we have not cracked the code of DNA. As far as I understand, what we do know about gene expression is simply the manufacturing and regulation of protein production - perhaps there are deeper layers of information hidden inside the structure of DNA, and these apparent junk spots are actually parts of this information structure - pure speculation here, but would like to hear other's thoughts...
"Junk DNA" is a rather unfortunate term. "Non-coding" is probably a better description. There are a lot of bits of so-called junk DNA (not all, by any stretch) that have a genome-level function, from structural to chromosome silencing. Some bits don't seem to have a function currently (like HERV retroviral insertions), but may end up being incorporated into an exon via mutation. We haven't figured out what everything does, yet, and some of it may in fact be "junk" (like the repetitious Alu sequences).
quote:
So this genetic drift would also be a random process, but is it not interesting that such a drift would be expressed as a gradual phenotypical change? The (non-hotspot) mutations that facilitated this drift may indeed be random but the fact that they resulted in a gradual change in a given phenotype may indicate some deeper mathematical pattern - maybe something to do with the homology of the organism.
Hmm, genetic drift is a population-level phenomenon relating to a random walk in variation of alleles simply due to chance. It's mostly observed in small, isolated populations. Certain variations may become fixed or even disappear completely. I suppose it's possible that this could lead to gradual phenotypical change - it's been seen to contribute to speciation, for example. However, that aspect is a very rare occurrance, and is often overwhelmed by other factors. In addition, there's no reason that this gradual drift can't reverse itself when alleles that were starting to predominate simply vanished. I'm afraid drift won't help you much.
quote:
Yes exactly it would be hitchhiking - I guess my biggest question is how to explain gradual phenotypical changes - it doesn't jive well with my instinct to think of it as purely random - random in the sense that the mutations may occur at random (stochastically as you said) yes - but the fact that these random changes give rise to patterned growth may imply that selection alone may not account for this. This is not necessarily to say that there is intelligence governing the principles of evolution - but perhaps that there may be hidden (at least at present) patterns within DNA that allow for interesting and gradual phenotypical progressions even with a random mutative engine.
I think the reason it doesn't jive well is because you're forgetting the key "non-random" part of the equation. Natural selection is the primary engine of evolution. Random mutation simply generates the variation - a nearly continuous process - upon which natural selection operates. Directional selection - where some change in a trait provides a net marginal fitness gain (or loss!) over the generations - has been observed. It can gradually increase or decrease the measure of some trait. Again, however, you're dealing with a population-level phenomenon over lots of generations. I'm not sure how you're able to say that patterned growth of a specific trait may not be explainable by natural selection. As I noted previously, some traits are fitness-neutral in and of themselves, but may vary in proportion to some other trait, as Mammuthus pointed out with his linkage disequilibrium explanation.

This message is a reply to:
 Message 21 by [xeno]Julios, posted 12-20-2002 2:23 PM [xeno]Julios has replied

Replies to this message:
 Message 26 by [xeno]Julios, posted 12-25-2002 3:25 AM Quetzal has not replied

  
[xeno]Julios
Inactive Member


Message 26 of 33 (27826)
12-25-2002 3:25 AM
Reply to: Message 25 by Quetzal
12-23-2002 4:43 AM


Thanks for the reply Quetzal
quote:
Originally posted by Quetzal:
I think the reason it doesn't jive well is because you're forgetting the key "non-random" part of the equation. Natural selection is the primary engine of evolution. Random mutation simply generates the variation - a nearly continuous process - upon which natural selection operates.
I haven't forgotten this part at all - the way I see it, the mutations determine which genotypes are "put to the test" or "judged by the context of environment", while natural selection determines which genotypes are more likely to survive.
Thus, one could argue that mutation is just as much an engine of evolution as natural selection.
Natural selection cannot explain the arising of phenotypes or changes of phenotypes, it can only explain which ones remain, and which changes are allowed to continue.
I still find it mind boggling that phenotypes can change gradually with random mutation.

This message is a reply to:
 Message 25 by Quetzal, posted 12-23-2002 4:43 AM Quetzal has not replied

  
[xeno]Julios
Inactive Member


Message 27 of 33 (27827)
12-25-2002 3:27 AM
Reply to: Message 24 by Brad McFall
12-23-2002 12:09 AM


quote:
Originally posted by Brad McFall:
Yes, but I need to "cool" down from the "holland" interaction. By "hot spot" I meant merely a short cut for my understanding of geneic balance and the whole issue of the position effect in general genetics and as for herpetology that will take some telling too. I will try to go back over all this with a fine toothed comb as soon as I dont feel like reading Einstein anymore.
I have no idea what you're talking about. Please try to structure your posts coherently and logically. Are you sure you're posting in the right thread?

This message is a reply to:
 Message 24 by Brad McFall, posted 12-23-2002 12:09 AM Brad McFall has replied

Replies to this message:
 Message 28 by Brad McFall, posted 12-25-2002 2:59 PM [xeno]Julios has not replied

  
Brad McFall
Member (Idle past 5033 days)
Posts: 3428
From: Ithaca,NY, USA
Joined: 12-20-2001


Message 28 of 33 (27850)
12-25-2002 2:59 PM
Reply to: Message 27 by [xeno]Julios
12-25-2002 3:27 AM


That's OK then, pretend I said nothing. I am posting in the right thread and as you see when I give no thought but post from knowledge which is often sufficient to remand a reply you can not follow it so I need time to compose my self. What I post on other threads effects my mood and does incline my scripting somewhat. You all here have been asking me too many question too fast that unless I use shortcuts of my own devising I should not post. Momentum was a subject I was dealing with IN DEPTH on a competitors site and am certain that the same would be applicable here (only I have not kept all the posts so I must use my brain and not a computer to do the work, and that takes time). I have very strong opnions about sociobiology and I must work hard to give as balanced a presentation as possible. Please just igore me for now I will try to pick up the straight biology as soon as possible.

This message is a reply to:
 Message 27 by [xeno]Julios, posted 12-25-2002 3:27 AM [xeno]Julios has not replied

  
Chavalon
Inactive Member


Message 29 of 33 (27864)
12-25-2002 6:38 PM
Reply to: Message 1 by [xeno]Julios
12-16-2002 8:15 AM


Hi [Xeno]Julius
Another take on your interesting question(s) -
If you’re asking whether there is anything intrinsic to the chemistry of DNA which makes some kinds of changes in phenotypes (‘bodies and what they do’) more likely than others, then the answer does seem to be no at the micro level of individual DNA bases. By analogy, there is nothing intrinsic to the alphabet that makes a number of random changes in single letters likely to alter the meaning of a written text in a consistent way.
But it is easy to imagine that some kinds of phenotypic change are easier than others, just because the laws of physics, geometry and materials science work the way they do. D’Arcy (his first name) Thompson wrote a classic book about this in 1917 called ‘On Growth and Form’. It’s perhaps the oldest biology book continuously in print apart from Darwin’s stuff.
A sketch of Thompson’s, showing a simple geometric relation between different species which face different selection pressures:
Center for Imaging Science | Page not found
More recently the work of David Raup has shown that many shapes closely resembling snail shells can be generated with a simple 3-parameter equation. Try it here -
http://members.aol.com/macops/Raup.html
but perhaps that there may be hidden (at least at present) patterns within DNA that allow for interesting and gradual phenotypical progressions even with a random mutative engine.
The interactions of genes during embryogenesis may very well have their own ‘rules of grammar’ that lead to some things being easier than others to ‘say’ with economy and elegance. Such phenotypic changes would be the ones most likely to appear by chance.

This message is a reply to:
 Message 1 by [xeno]Julios, posted 12-16-2002 8:15 AM [xeno]Julios has not replied

  
peter borger
Member (Idle past 7665 days)
Posts: 965
From: australia
Joined: 07-05-2002


Message 30 of 33 (27886)
12-26-2002 8:14 AM
Reply to: Message 1 by [xeno]Julios
12-16-2002 8:15 AM


Dear XJ,
Your example is a nice illustration of a trait that cannot be explained by evolution through random mutation and selection, and rightfully you wonder:
Is it theoretically plausible to posit such a phenomenon (evolutionary "momentum"), given the known mechanisms of mutation? What about any speculative mechanisms?
Is there any evidence of such phenomena?
PB: You've had several responses from neodarwians who try to keep up the appearance of randomness of mutations, and they have to since otherwise the theory falls. Hoever, by now they should know better, since it has been demonstrated that a class of mutations operates in the genome in a non-random fashion. For examples see my threads: "molecular genetic evidence against random mutation", "Dr Page's best example of common descent readily -and better- explained by the GUToB", and "More non-random evolution".
Any questions? Don't hesitate to ask,
Best wishes,
Peter

This message is a reply to:
 Message 1 by [xeno]Julios, posted 12-16-2002 8:15 AM [xeno]Julios has not replied

Replies to this message:
 Message 31 by Adminnemooseus, posted 12-26-2002 10:26 AM peter borger has replied

  
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