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Author Topic:   Is there really such a thing as a beneficial mutation?
Percy
Member
Posts: 20498
From: New Hampshire
Joined: 12-23-2000
Member Rating: 8.3


Message 151 of 223 (343327)
08-25-2006 12:18 PM
Reply to: Message 147 by crashfrog
08-25-2006 12:04 PM


Re: Trade-offs
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


This message is a reply to:
 Message 147 by crashfrog, posted 08-25-2006 12:04 PM crashfrog has responded

Replies to this message:
 Message 152 by crashfrog, posted 08-25-2006 12:32 PM Percy has responded
 Message 170 by Faith, posted 08-25-2006 5:53 PM Percy has not yet responded
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crashfrog
Member (Idle past 577 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 152 of 223 (343334)
08-25-2006 12:32 PM
Reply to: Message 151 by Percy
08-25-2006 12:18 PM


Re: Trade-offs
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 see how that case can be made. I don't know how you could look at the world, or even our own country, and see a situation where there's no competition for mates or for resources.

I mean, last I checked, people weren't mating at random, but were making choices about who they chose to have children with; and 99% of the Earth's human population fails to enjoy the quality of medical care and attention that you refer to as supposedly "shielding" us from natural selection. I think the idea that natural selection has ceased its action on the human race is largely mythical. Even if there's a microscopic portion of human beings for whom historic environmental pressures have been eased - us - that's not the case for the majority of humans, and for every human, sexual selection is very much still in play. And even the environment of Western wealth and affluence comes with its own environmental pressures. I can probably find a few examples of beneficial mutations that are being selected for as defenses against the saturated fats and refined sugars in the Western diet.

Sure, the stuff I mentioned might not have a direct relationship to genetics. But if we're talking about the wholesale reduction of human genetic fitness in the past 6000 years, why are we so much smarter than the people who lived at that time? Why is it that we're the ones with the rocket ships and the Internet, and not them? Why is it that we're the ones for whom bubonic plague is just a weekend's worth of sniffles, and they're the ones for whom it was the harbinger of the apocalypse? (Hyperbole, BTW.)

Science fiction and fantasy give me a pretty good idea of what it looks like when a civilization degrades from a perfect state. Grunting savages worshipping in the shadows of machines that are slowly succumbing to entropy with no one smart enough to do simple maintenence. It's the world of Dungeons and Dragons campaigns; it's the world of Asimov's Foundation novels.

Doesn't really look like that, does it? Antiques are primitive, not god-like. Old computers are hilarious in the unsophistication of their design, not mysteries of ancient know-how that our modern engineer-preists guard jealously at the same time that they abandon hope of understanding them.

Ok, more hyperbole. But that's what I would expect it to look like, eventually, after millenia of decline. And it doesn't look like that. We're getting better, not worse.


This message is a reply to:
 Message 151 by Percy, posted 08-25-2006 12:18 PM Percy has responded

Replies to this message:
 Message 155 by Percy, posted 08-25-2006 2:05 PM crashfrog has responded

  
Wounded King
Member (Idle past 3205 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 153 of 223 (343336)
08-25-2006 12:40 PM
Reply to: Message 131 by Percy
08-25-2006 10:56 AM


Re: Trade-offs
why you don't accept that, for example, the wisdom tooth mutation is beneficial

I'm not sure that I really accept that the wisdom tooth mutation, if there is one specific mutation that we are discussing, is beneficial in anything other than a colloquial sense.

Certainly not getting impacted wisdom teeth would make life nicer for people but I doubt the number of cases where they would lead to someone dying before having a chance to reproduce are all that significant, or at least they wouldn't have been before people started living longer and procreating later.

Wisdom teeth seem rather to be an example of a trait which is becoming vestigial due to no longer being beneficial, there are a number of mutations associated with hypodontia (tooth loss) perhaps the selective constraints on such mutations are simply much lower in modern populations. Other than a miniscule saving in bodily resources I'm not sure how much of a reproductive benefit this would confer. I can only find one reference that seems particularly relevant which suggests there is a possibility that certain pax9 tooth agenesis related mutants may have a beneficial effect (Pereira et al, 2006).

Any actual detailed population genetic research on the topic would probably be helpful in clearing up this question.

TTFN,

WK


This message is a reply to:
 Message 131 by Percy, posted 08-25-2006 10:56 AM Percy has responded

Replies to this message:
 Message 154 by Percy, posted 08-25-2006 1:50 PM Wounded King has not yet responded
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Percy
Member
Posts: 20498
From: New Hampshire
Joined: 12-23-2000
Member Rating: 8.3


Message 154 of 223 (343355)
08-25-2006 1:50 PM
Reply to: Message 153 by Wounded King
08-25-2006 12:40 PM


Re: Trade-offs
Wounded King writes:

Certainly not getting impacted wisdom teeth would make life nicer for people but I doubt the number of cases where they would lead to someone dying before having a chance to reproduce are all that significant, or at least they wouldn't have been before people started living longer and procreating later.

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.

--Percy

Edited by Percy, : Fix grammar.


This message is a reply to:
 Message 153 by Wounded King, posted 08-25-2006 12:40 PM Wounded King has not yet responded

  
Percy
Member
Posts: 20498
From: New Hampshire
Joined: 12-23-2000
Member Rating: 8.3


Message 155 of 223 (343359)
08-25-2006 2:05 PM
Reply to: Message 152 by crashfrog
08-25-2006 12:32 PM


Re: Trade-offs
crashfrog writes:

I mean, last I checked, people weren't mating at random, but were making choices about who they chose to have children with; and 99% of the Earth's human population fails to enjoy the quality of medical care and attention that you refer to as supposedly "shielding" us from natural selection. I think the idea that natural selection has ceased its action on the human race is largely mythical.

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.

Sure, the stuff I mentioned might not have a direct relationship to genetics. But if we're talking about the wholesale reduction of human genetic fitness in the past 6000 years, why are we so much smarter than the people who lived at that time? Why is it that we're the ones with the rocket ships and the Internet, and not them? Why is it that we're the ones for whom bubonic plague is just a weekend's worth of sniffles, and they're the ones for whom it was the harbinger of the apocalypse? (Hyperbole, BTW.)

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.

We're getting better, not worse.

I think you're confusing our technology with us. Our technology has continuously improved. Ourselves as biological organisms show no such improvement.

--Percy


This message is a reply to:
 Message 152 by crashfrog, posted 08-25-2006 12:32 PM crashfrog has responded

Replies to this message:
 Message 156 by crashfrog, posted 08-25-2006 2:36 PM Percy has responded

  
crashfrog
Member (Idle past 577 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 156 of 223 (343367)
08-25-2006 2:36 PM
Reply to: Message 155 by Percy
08-25-2006 2:05 PM


Re: Trade-offs
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.

We're probably about to careen off-topic, but I would just like to say that while these are things very often asserted to be "insulated" from natural selection, it's not immediately obvious to me that this is the case.

Just because someone has a physical trait that, in our modern times, they choose to improve with technology, that doesn't seem to immediately indicate to me that, in a time without technology, they would have been "selected against." Stories about some primitive four-eyes who "gets eaten by a tiger because he can't see as well" seem more like jokes than genuine speculations on evolutionary pressures.

I mean let's be serious. Tigers have been known to hit 50 MPH in a flat run and can leap over 10 meters. If you're close enough to a hidden tiger to see it, even with 20/20 vision, what possible advantage do you gain from that? And also - tigers don't live in Africa.

What I'm saying is, our technologies haven't nearly changed the pressures on us as completely as you seem to suggest. Somebody who uses glasses today might simply have asked his buddies "hey, do you see any mammoths over there?" back then and completely ameliorated the disadvantages of having 20/200 vision or whatever. People have been organized into cooperative communities for all of history and that's a "technology" that overcomes a lot of these physical variations right there.

The pelvis thing, though. You're probably right about that.


This message is a reply to:
 Message 155 by Percy, posted 08-25-2006 2:05 PM Percy has responded

Replies to this message:
 Message 157 by Percy, posted 08-25-2006 2:57 PM crashfrog has responded

  
Percy
Member
Posts: 20498
From: New Hampshire
Joined: 12-23-2000
Member Rating: 8.3


Message 157 of 223 (343371)
08-25-2006 2:57 PM
Reply to: Message 156 by crashfrog
08-25-2006 2:36 PM


Re: Trade-offs
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


This message is a reply to:
 Message 156 by crashfrog, posted 08-25-2006 2:36 PM crashfrog has responded

Replies to this message:
 Message 158 by crashfrog, posted 08-25-2006 3:50 PM Percy has responded

  
crashfrog
Member (Idle past 577 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 158 of 223 (343378)
08-25-2006 3:50 PM
Reply to: Message 157 by Percy
08-25-2006 2:57 PM


Re: Trade-offs
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.

If it was such an advantage that lacking it was a death sentence, why would there be such a range in visual acuity among humans? We've only had effective perscription eyewear for maybe 100-200 years now. That's an eyeblink, maybe 6-8 generations. Not nearly enough time for the great variation in human eyesight to be a function how perscription eyewear keeps us from being hit by buses at age 12 or something.

Look, I can imagine plenty of situations where sharp perception spells the difference between life and death. Just as the difference between standing here or standing there means the difference, occasionally, between being the guy that the rock crushes and being the guy that moves in on his girl after the funeral. I just can't imagine enough such situations that, in aggregate, they represent a serious selective pressure. Some amount of differential survival is always just random noise.

I'm sorry to harp this point, I really am. And it seems like there's only so much disagreeing you can do with Percy before it's all "how can someone so smart be so nuts?!" But everybody swings that old chestnut about how "we're so smart nowadays that we've conquered natural selection!" but it seems like nobody ever gives it much thought. And when you do think about it, it pretty much evaporates. Sure, life in a city is a different environment than life in the wilderness. But the idea that we're somehow weighed down by all these "weak" people we allow to survive is pretty ridiculous. Aren't they the strong ones, if they're so skilled at manipulating the rest of us into building a civilization designed for their benefit?


This message is a reply to:
 Message 157 by Percy, posted 08-25-2006 2:57 PM Percy has responded

Replies to this message:
 Message 160 by Percy, posted 08-25-2006 4:22 PM crashfrog has responded

  
Percy
Member
Posts: 20498
From: New Hampshire
Joined: 12-23-2000
Member Rating: 8.3


Message 159 of 223 (343379)
08-25-2006 3:53 PM
Reply to: Message 153 by Wounded King
08-25-2006 12:40 PM


Re: Trade-offs
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?:

Abnet et al.1 show that tooth loss is associated with increased risk of mortality from upper gastrointestinal cancer, heart diseases, and stroke.

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:

Breaking it down by numbers, the risk was 50 percent higher for men with 17 to 24 teeth, 74 percent higher for men with 11 to 16 teeth, and 66 percent higher for men with 10 or fewer teeth.

Like, whoa!! Far worse than I would have guessed.

--Percy


This message is a reply to:
 Message 153 by Wounded King, posted 08-25-2006 12:40 PM Wounded King has not yet responded

  
Percy
Member
Posts: 20498
From: New Hampshire
Joined: 12-23-2000
Member Rating: 8.3


Message 160 of 223 (343382)
08-25-2006 4:22 PM
Reply to: Message 158 by crashfrog
08-25-2006 3:50 PM


Re: Trade-offs
If it was such an advantage that lacking it was a death sentence, why would there be such a range in visual acuity among humans? We've only had effective perscription eyewear for maybe 100-200 years now.

This guy died in 1645:


Click to enlarge

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.

That's an eyeblink, maybe 6-8 generations. Not nearly enough time...

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.

crashfrog writes:

I just can't imagine...

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


This message is a reply to:
 Message 158 by crashfrog, posted 08-25-2006 3:50 PM crashfrog has responded

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Faith 
Suspended Member (Idle past 555 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 161 of 223 (343388)
08-25-2006 5:33 PM
Reply to: Message 142 by crashfrog
08-25-2006 11:46 AM


Re: No such list
It's a basically settled issue, so no one bothers to keep track anymore. Anyway, as Percy said in the other thread, every gene in every organism, every cellular function, every protein, every regulatory structure, everything, all started out as beneficial mutations.

According to the ToE. All based on the theory, no actual evidence.

Creationism says most of our genetic package was given in the beginning. You simply define our theory out of existence by your theory. There is no actual evidence.


This message is a reply to:
 Message 142 by crashfrog, posted 08-25-2006 11:46 AM crashfrog has not yet responded

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Faith 
Suspended Member (Idle past 555 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 162 of 223 (343389)
08-25-2006 5:36 PM
Reply to: Message 143 by Jazzns
08-25-2006 11:52 AM


I'll get to the CCR5 gene in my own good time, thanks. Schraf originally brought it up and I have not been reading her posts.

This message is a reply to:
 Message 143 by Jazzns, posted 08-25-2006 11:52 AM Jazzns has responded

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 Message 164 by Jazzns, posted 08-25-2006 5:44 PM Faith has responded

  
Faith 
Suspended Member (Idle past 555 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 163 of 223 (343390)
08-25-2006 5:40 PM
Reply to: Message 144 by Percy
08-25-2006 11:56 AM


Re: Trade-offs
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.

I find this a truly laughable example of a "technical argument" you are demanding that I answer, this list of imaginative hypotheses. Oh I'm not saying it's not plausible. Much of ToE thinking is plausible. It's just a bunch of plausibilities with SO little actual evidence to back up the "technical argument."

Being browbeaten for this sort of "failure" is just too depressing for words.


This message is a reply to:
 Message 144 by Percy, posted 08-25-2006 11:56 AM Percy has responded

Replies to this message:
 Message 168 by Percy, posted 08-25-2006 5:49 PM Faith has responded

  
Jazzns
Member (Idle past 3022 days)
Posts: 2657
From: A Better America
Joined: 07-23-2004


Message 164 of 223 (343391)
08-25-2006 5:44 PM
Reply to: Message 162 by Faith
08-25-2006 5:36 PM


So has Aegist among others.

Others such as myself, crashfrog, and Aegist have also given more examples than CCR5.

The example that seems to permeate this discussion based on SCD is also no longer an issue when concerning Hemoglobin C. That is the one I brought up because of your specific complaint of pitting "disease against disease". The only negative effect of Hemo C is slight anemia and it is a novel allele. It meets all your critera for a beneficial mutation. It is something that was not part of the previous genetic potential. It does not confer a disease. It provides a substantial benefit to those that have it.


Of course, biblical creationists are committed to belief in God's written Word, the Bible, which forbids bearing false witness; --AIG (lest they forget)

This message is a reply to:
 Message 162 by Faith, posted 08-25-2006 5:36 PM Faith has responded

Replies to this message:
 Message 171 by Faith, posted 08-25-2006 6:00 PM Jazzns has responded

  
Faith 
Suspended Member (Idle past 555 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 165 of 223 (343392)
08-25-2006 5:45 PM
Reply to: Message 144 by Percy
08-25-2006 11:56 AM


Re: Trade-offs
How could I guess the probable role of wisdom teeth in our ancestry? Just because losing them is no felt loss now, and in some cases (how many? Nobody has said) may be a relief from crowded teeth and other ills, doesn't mean it isn't REALLY a deleterious mutation, perhaps accommodating to who-knows-how-many previous losses by mutation.

This argument is just speculation.

Of course it is. It is on the same level as the "technical argument" you put forward. It is my theory answering your theory.

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.

Well, imagine that, Percy. Doesn't that sort of go with my theory? How is that an objection?

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.

Oh THAT's clever. One thing evolutionists do VERY well is come up with plausible hypotheses and scenarios. Calling that a "technical argument" is really a joke.


This message is a reply to:
 Message 144 by Percy, posted 08-25-2006 11:56 AM Percy has not yet responded

  
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