Is there really such a thing as a beneficial mutation?

Hi Faith,You started out trying to learn enough about mutations to understand how they could be beneficial, but you were gone for a short while during which time mjfloresta drew the thread off-topic. AdminNWR issued a topic drift alert, and when you returned you went into denial mode, triggered perhaps by Jazzns's Message 73. Could we return to discussion?Perhaps the confusion is related to the definition of beneficial. There's definitely a component of your approach to to thinking this that seems to be saying, "How could a mistake ever be beneficial? This is obviously impossible!"A beneficial mutation is one that confers differential reproductive success upon the organism. Differential reproductive success means that the organism with the mutation is differently successful than other organisms without the mutation at producing offspring. If the mutation causes the organism to become better at producing offspring, then to a degree governed by the laws of genetics and the details of the organism's reproductive process its offspring inherit the mutation, and it spreads throughout the population because of the greater ability to produce offspring.But if the mutation causes the organism to become less successful at producing offspring, then the mutation tends not to spread through the population because the organism produces less offspring than other individuals. In the worst case the mutation causes death before the organism reaches sexual maturity, the organism produces no offspring at all, and the mutation dies out in a single generation.What's most important about a mutation is its effect on an organism's ability to produce offspring. If the mutation enables it to produce more offspring, then it is beneficial. If the mutation makes the organism less able to produce offspring, then it is harmful.Another component to your approach to thinking about beneficial mutations seems related not to single mutations during single reproductive events, but multiple beneficial mutations over long periods of time and many reproductive events. But once you've accepted the possibility of a beneficial mutation in a single reproductive event, since the probability of a beneficial mutation is largely independent of past reproductive events, future reproductive events are about as likely to produce beneficial mutations as ones in the past. Just like a throw in dice of boxcars (6 on each of two die) does not affect the likelihood of the next throw being boxcars, a reproductive event resulting in a beneficial mutation does not affect the likelihood of another beneficial mutation in the next reproductive event. I thought you said you were going to try and understand things this time. Where did you get the idea that functionless mutations snuff out alleles? It's not fact, but it *is* theory supported by massive piles of evidence. You're now denying a process that is so well established that students in biology programs observe this very process experimentally when they do their genetics labs. This is why people keep mentioning bacterial experiments to you. The bacterial experiments aren't popular because the process only happens in bacteria. They're popular because they can be done in less than a week. The same kind of reproductive errors and selection observed with bacteria are observed with other organisms, both in the lab and in the wild, but over much longer time periods. I guarantee you that no one living in the world today possesses a fatal mutation that is dominant expressive. That's because they're filtered (selected against) very well. In other words, 100% of fatal mutations are filtered. Mutations that are less than 100% fatal or that have recessive qualities so they can easily hide in the genome are of course filtered to a lesser degree. But since they do not contribute positively to people's differential reproductive success and because they can, under conditions that cause them to be expressed, contribute negatively to differential reproductive success, they cannot help but be filtered to some degree from the population because the affected individuals produce fewer offspring. I've seen no indication that you've understood anything on the short list so far, though that hasn't stopped you from saying you're unimpressed and rejecting them. You seem to believe it's valid to conclude that that which you don't yet understand is false. Nobody minds this. The problem is rejecting arguments and evidence before you understand them. Could we once more leave denial aside and go back to discussion?--Percy

You supposedly joined this thread to understand what evolution says about beneficial mutations. It was pointed out in other threads that you were making many inaccurate statements and needed to understand evolution better before you could criticize it. It was also pointed out that understanding it isn't the same thing as accepting it, but that such an understanding was necessary in order to criticize it for things it actually says, rather than things you think it says.But after Jazzns's Message 77 you changed tack and decided that the ToE perspective is off-limits, saying things like this: You began participation in this thread with the apparent intention of understanding how ToE views beneficial mutations, but now you seem to believe that understanding anything from a ToE perspective is something you're going to actively avoid. I'd like to see you return to your original mode of participation by addressing the substance of my Message 117.--Percy

You've drawn a distinction without any meaning. The field of science that deals with mutations is genetics, which is part of the modern synthesis of evolutionary theory. Evolution *is* science, so science and evolution will say the same thing about mutations.--Percy

This is a dismissal, not a continuation of a discussion. Understanding what a beneficial mutation is fundamental to having sufficient common ground for a meaningful discussion to take place. Understanding this is fundamental to pursuing the topic of this thread, which is whether there is any such thing as a beneficial mutation.So if you understand the explanation I provided (and you claim you do), and if you don't accept it, then the next step is to explain why. By explaining why, I mean by referencing parts of the explanation about beneficial mutations, and not by dismissals like references to "this tunnel-visioned definition" and statements like "evolution can't happen." The only thing my argument using the dice had in common with my earlier argument using a die is dice. They were two completely different arguments. The early one made a point that the effect of random events on something cannot be considered some inherent part of the original objects. It was made in reply to your argument that mutations should be considered part of the original genome.This time I used dice for a completely different argument, that random events are independent. You say you don't dispute this. Good.But you ignored the rest of the argument, that part of the reason you don't accept the possibility of beneficial mutations is because you don't believe a chain of them is possible. Did I get that wrong? Do you accept that a beneficial mutation occurring in one generation does not affect the possibility of a beneficial mutation occurring in the next generation? That's what we're trying to remedy, remember? Your misunderstandings? A mutation cannot "snuff out" alleles. One organism of a population losing an allele because of a mutation that transforms it to a new allele cannot affect all the other individuals in the population that possess the old allele.But it can happen over time that a new allele out competes other alleles of the same gene, even to the point of extinction for those alleles. This involves differential reproductive success and selection. If the new allele allows organisms possessing it to produce more offspring and more competitive offspring, then it could actually, over time, "snuff out" some other alleles. I think your only example was human beings, and I agreed with you. The comforts of modern civilization and the benefits of modern medicine insulate us from traditional selection factors. But if WW-III sends us back to the stone age then you'll see plenty of selection going on. But they are "of the same sort of thing". The time scales are longer and the reproduction is sexual, but it is still mutations and selection. If you don't think it is "of the same sort of thing", then you have to explain why. This *is* science, Faith. Evolution *is* science. And if I've been sufficiently careful, then most of this post is about the topic of this thread, beneficial mutations. If you don't want to talk about beneficial mutations, then don't reply. No, I don't think you do. I think you're just claiming that you do so you won't have to face them anymore. If you understood them then you'd be able to explain, at a technical level, why you don't accept that, for example, the wisdom tooth mutation is beneficial, something you have yet to do.--Percy

I think you must be using an incorrect definition of science. You seem offended when evolution is called science, as if calling it science conferred upon it some kind of imunity from questioning. This is not the case. No scientific field is immune from questioning.Evolution is science because it satisfies the definition of science (falsifiability, replicability, predictive power) and because its theories developed under the auspices of the scientific method (hypothesis, experiment, observation, assessment, theory). I think everyone on the evolution side is committed to supporting its theories by providing the evidence behind them.--Percy

Yes, Faith, those explanations were on a technical level appropriate for this forum. They addressed the issue directly and specifically. They were not general dismissals such as you do in your next sentence: When specific technical arguments are made then you need to address them, not dismiss them as "wild imaginative hypotheses". In a prehistoric context, the wisdom tooth mutations that cause some or all wisdom teeth to never appear are beneficial because wisdom teeth cause several different types of problems. A common one is infections, usually due to one of the types of impaction. The infections can easily spread to the cheek and neck. Untreated, such infections can eventually lead to death. Short of death, the infections can cause disabilities, such as loss of flexibility in the neck, important for survival in prehistoric times.Decay is another risk, since impacted teeth frequently create skin pockets where material gathers. Those infections that don't directly lead to death can leave the individual weakened and less able to fight off other diseases and infections, leading to disability and/or death.Cysts can form that cause bone destruction and displacement and damage to nearby teeth, making eating difficult.During periods when the individual is weakened due to wisdom teeth problems, either pain or infection or both, he is less capable of competing for survival, and is also less capable of providing for his family, important since his children carry his genes.Those with sufficiently severe wisdom tooth infections to cause disfigurement have more difficulty attracting a mate.A technical rebuttal to these points would address the specifics of them. It would not be a dismissal such as the one I recall you making last time this came up, something about just not being able to believe that a mistake could cause something good to happen.Finally, let me address your technical response: This argument is just speculation. You speculate about an unknown positive role for wisdom teeth in our ancestors, and then you speculate about unknown deleterious effects from not having wisdom teeth. And your speculations have hard evidence against them. Our evolutionary ancestors had larger jaws. As brain size increased the jaw shrunk, so in most people there's now not enough room in our jaw for all the teeth. Our evolutionary ancestors did not suffer from their wisdom teeth because their larger jaws more easily accommodated them.As for deleterious effects from not having wisdom teeth, none have been identified so far. Aside from the risks associated with the extraction itself that are part of any medical procedure to varying degrees, wisdom tooth extraction has no downside, no deleterious health effects, and only long-term benefits in the form of freedom from the associated pain, infection and decay problems.So please address the specific points I made about the benefits of the wisdom tooth gene and not having wisdom teeth.--PercyEdited by Percy, : Wisdom truth => wisdom tooth

I don't see what any of these arguments in the last two paragraphs have to do with beneficial mutations. The improvements you're talking about aren't genetic but cultural, like IQ, or technical, like modern medicine. I agree with Faith's earlier argument that the genome of the human race is over time becoming less and less robust (I know that's very non-specific, but I think the meaning is clear) because our civilization and technology protect us from the traditional forces of selection. I don't think Faith understands this reason for accepting her position, but that's another matter.--Percy

Prehistoric times. I characterized the problems wisdom teeth would have presented to people in prehistoric times. As I said in my reply to Crash on a different topic, we've largely insulated ourselves from traditional selection pressures through technology, so I agree that today we've largely isolated ourselves from the deleterious impact of not having the wisdom tooth gene.But that's just us, with our computers and our company provided health care (many of us) and our nice warm (or air conditioned) homes. Modern health care is not available world wide, and many people still live under primitive conditions. These regions are subject to the same wisdom teeth problems as people in prehistoric times. Any mutation which does nothing but eliminate health problems can only be advantageous.I wonder if you're only considering the wisdom tooth gene by itself in isolation. If you have in mind people whose only problem is an infection from a wisdom tooth impaction, even when they have access to no modern medicine at all, maybe it seems to you that it just couldn't be all that bad, that the only difference is freedom from pain (if you believe infections aren't a problem for pre-scientific peoples I disagree, but I won't pursue that here). But now consider the whole range of things that can happen. A person gets sick with a virus from which they might normally recover, but it weakens their immune system and opportunistic bacteria not normally very active in the mouth infect an impacted wisdom tooth and spread virulently into the blood stream where they reach the brain and quickly cause inflammation, swelling and death.In the Galápagos Islands they study birds where fractions of millimeters in beak length make a difference to survival, depending upon whether recent seasons have been wet or dry. Wisdom tooth impaction issues seem to me to loom much larger in potential impact than sub-millimeter beak size changes.--PercyEdited by Percy, : Fix grammar.

And I didn't mean to imply it had. What I meant when I said we're no longer exposed to traditional forces of selection were those selection forces that affected our distant ancestors but don't affect us today. Examples of such things are natural resistance to disease, eyesight, physical attributes (strength, speed, agility, coordination, size, height, bone-size, pelvis width (women only), etc.), and so forth.And I agree that there are many parts of the world where these selection forces are still a significant factor. I'm not sure how strong a filter to apply in response to your "hyperbole" modifier, but there's no indication we're smarter today than we were. The argument you offer of improving technology springs from the invention of language and writing, making it possible for bodies of knowledge to grow far beyond what can be accumulated in a single generation, and promulgating knowledge geographically by way of books far beyond what people could communicate personally. I think you're confusing our technology with us. Our technology has continuously improved. Ourselves as biological organisms show no such improvement.--Percy

You and WK are a pair, unable to see or think of advantages where clear advantages exist. Considering all the millions of people throughout time through all their lives, they will be confronted with a huge variety of circumstances in some percentage of which better vision will confer a survival advantage.It's kind of a surprise that the same people who can argue that one light sensitive cell is better than none, and that two light sensitive cells is better than one, and so forth, can somehow deny that better vision confers a survival advantage.--Percy

I don't know how well this articles ties in directly with wisdom teeth, but this is from Commentary: Is tooth loss good or bad for general health?: The extract goes on to mention the difficulties of establishing causal relationships, and I didn't pay for access to the entire article so I don't know its conclusions, but I still think this emphasizes very well the point I made earlier. Problems with wisdom teeth go beyond just pain and occasional infections. The repercussions for overall health (they call it systemic health) cannot help but be bad, especially in pre-scientific peoples, and this study was conducted in the UK, not as advanced as Scotland, of course, but still pretty advanced. Here's another article titled Tooth Loss and the Risk of Stroke and Heart Disease. Similar conclusions, but limited to considering strokes and heart disease. And get this: Like, whoa!! Far worse than I would have guessed.--Percy

This guy died in 1645: So I guess maybe eyeglasses have been around for longer than 100-200 years?And it isn't just eyeglasses. It's that the visual acuity necessary for life under primitive conditions is greater than that for life on a farm, which is greater than that for life in a city. Your timeframe has already been shown to be off, but the more significant point is that there's no latency in evolution. As soon as an environmental change takes place, selection will be factor from then on. The impact of the change in evolutionary terms may be felt more and more dearly as time passes, it depends upon the strength and nature of the selection pressures, but they are felt immediately without delay. Regarding the specific example of eyesight, the degree of primitiveness of the conditions are important, also. There were far greater selection pressures regarding eyesight in primitive Patagonia than on primitive Figi. Argument from incredulity.Nothing you said counters the argument that civilization and modern medical technology insulate people from the types of selection pressures imposed on those living under primitive conditions. There's no escape from this conclusion.--Percy

I believe I said technical arguments appropriate for this forum. I listed a number of deleterious effects caused by the presence of wisdom teeth that are not imaginative hypotheses. Infection, decay, cysts, inability to eat, disfigurement, these are all factual risks, and if you noticed my replies to Wounded King there is also increased risk of heart disease, stroke and gastrointestinal problems. These are not hypotheses or plausibilities, they are evidence gathered through observation, studies and research.Dismissing all this evidence is what I meant before when I referred to your denial machine. If you really don't believe wisdom teeth are deleterious, then please address my list of deleterious effects and show how they either are fictitious or not really deleterious.--Percy

I'm not so sure it's as simple as this. If we use the example of vision and accept, merely for the sake of argument, that the vision of civilized peoples has declined in terms of visual acuity (i.e., resolution) and the ability to focus, then genomic diversity for vision was less in the distant past than it is today. In other words, a lesser percentage of people had bad vision in the past than today. Would a greater diversity in visual acuity and focal ability be a sign of robustness? In other words, is the fact that more people are born today with bad vision a sign of robustness?Again, I'm not trying to sneak in my stance on vision, it's just for the sake of argument. Rapidly, as in up until we became Homo sapiens sapiens? Or are you implying that our intelligence continued to evolve after the emergence of our species. If the latter, I grant the possibility, but I don't think there is any evidence supporting it. Unless you're arguing that modern man is more intelligent than ancient man of, say, 30,000 years ago, I would say that infant children of ancient men raised in the modern world would be more fit and more competitive, in the aggregate, than modern men.You need a standard measure if you want to measure the relative competitiveness of ancient and modern man, and I don't know what that would be. If we had a time machine, you couldn't take an ancient man into today and have him compete against modern men, he wouldn't have the necessary background and the results wouldn't be meaningful. But if he'd actually been from the ancient world but raised in the modern world I think he'd have an advantage.In the exact same way, you couldn't transport a modern man back to the ancient past and have him be competitive, either. He'd probably end up as something's dinner in a very short while. But if he'd been raised in the ancient world he'd probably do okay, but not as well as average.If I were to guess, I'd say that you and Crash see our modern technology as an indication that we're superior to ancient man. I don't see it that way. Our modern technology is just an inevitable development of thousands of years of gradually accumulating knowledge and expertise made possible through language and writing. I don't think I used the word vital, but vision *is* a selection factor, and it can be vital when considered across the broad spectrum of possibilities for vision. Clearly as vision approaches and reaches blindness it is a strong selection factor, but what you're saying is that when vision is not too far from normal that it isn't a selection factor, and that vision beyond a certain goodness level just doesn't affect selection one way or the other.This makes sense, but we haven't established whether current average visual ability among civilized people is above that point. Aside from Darwin's mention of the vision of Patagonians (I think in both Origins and in The Descent of Man, but I might be wrong about that, perhaps it was only mentioned in the latter) I haven't been able to find any on-line evidence that primitive peoples have better vision, on average, than civilized people, but neither have I found evidence to the contrary, though there's a 1930 paper by a Russian taking this contrary position but arguing only rhetorically without evidence. If such studies have been done or are done in the future, I think they'd back me up, but even if they didn't my original point is still valid. Modern technology insulates us from the many selection pressures, and if that technology were removed we would quickly find that civilized man really isn't as "robust", regardless of any claims of diversity, as those to whom primitive conditions are home.--Percy

Agreed, but one point I decided not to make in my post, erroneously believing that we probably already agreed on it, was that we have to decide what is an appropriate measure of robustness. Does it mean how well the organism is adapted to the present environment, in which case diversity is a disadvantage? Or does it mean how well the organism is prepared to meet unpredictable environmental changes, in which case diversity is an advantage? You anticipated this much further on in your post when you said, "Clearly, the reproductive fitness of its members in the current environment is one determinant."I think your preferred measure of robustness is to just say robustness==diversity. But the reason I introduced the term robustness was because I specifically did not mean to include diversity. I'm not married to the term robustness and am perfectly content if you'd like to propose another term, but what I had in mind was measuring how well the organism was adapted to the present environment. I don't know if I'd call it entropic, but this is not only true on a simple rational level, we know it is true because we have observed it. Cave fish that have completely lost vision are an example. I think you mean hereditary, not congenital. But this is a counterargument? Why not ask why all severe hereditary diseases haven't been purged from the genome long ago? While the Third World is poor and underdeveloped, and while there are certainly parts of the third world with primitive peoples, it isn't what I was thinking of when I used the term primitive. I don't recall exactly what I said, but I was referring to primitive peoples who live in direct contact with nature and who are relatively isolated from modern civilization and its conveniences. There are very few parts of the world like this today. But yes, I believe they have better vision. As I mentioned earlier, this was one of Darwin's observations about the native Patagonians, but I by no means consider his lone observation conclusive and await better evidence. I'm not a romantic, so it would be unusual for myths to drive my thinking, especially myths I don't buy into. Another factor in addition to vision that I believe separates primitive peoples from those in civilized regions is natural resistance to disease. This difference hasn't had long to develop since antibiotics and vaccines have been around for less than a century, and which way this goes is open to argument in both directions. Urban residents have throughout history been exposed to the dangers of epidemics and also simply to the risks of increased exposure due simply to population density, so it could be argued that they would have developed an increased resistance to disease. On the other hand, antibiotics and vaccines insulate people with access to modern medicine, which includes urban residents, from the selection pressures of many contagious diseases. It's probably impossible to say whether urban residents or primitive peoples have the best natural resistance to disease, but now that I think about it I bet that while there *are* differences, it could by disease type rather than a general advantage overall. In other words, for some types of diseases primitive peoples might have better natural resistance, while for others urbanites might have better resistance.The main point is that I'm not proposing anything novel. I'm only stating the traditional evolutionary view that selection pressures operate on expressed characteristics, and that things like vision and resistance to disease are definitely expressed characteristics. Whether or not we agree on the details, we all accept that humans are subject to selection pressures. Well, we probably agree more than we disagree. I probably can't go as far as saying that intelligence makes diversity possible, but I certainly agree that diversity is a central factor for a population's adaptation and long term survival.--Percy