Mutational deterministic hypothesis

[Atreides]

This is basically an evolution thread. With a new idea that's 20 years old. Here's the link that started it.

 

The old idea's that organisms started having sex because mixing DNA would produce more mutations and we'd have wings. Or something.

 

Anyway the "new" idea's the ancestral organisms started getting it on because (if I understand this right) if an individual gets stuck with too many bad mutations passed down to it it dies off.

 

Read the link for a better explanation.

 

The new work could help test a hypothesis first proposed nearly 20 years ago, stating that sex evolved as a way to purge harmful mutations from a population. According to this view, the random shuffling of genes through sex will sometimes have the effect of concentrating many harmful mutations into single individuals.

 

These individuals will be less healthy than their peers, and therefore more likely to be weeded out by natural selection, the thinking goes.

 

Now, assuming this works and it sounds reasonable - individuals with multiple negative mutations being "weeded out" - what's the implications in mankind's future where medical science has become advanced enough to save those negative epistasis(es?) and have them reasonably healthy and able to pass on their genes?

 

By the way, here's another bone to contemplate before closing:

 

"Most mutations are actually harmful, so anything that helps populations get rid of their harmful mutations is going to be important," Azevedo said. "The more interesting side of evolution is all the beneficial mutations that leads to complex structures, but the dirty work of evolution is to get rid of bad mutations, and that's where sex seems to play a role."

[Nexus]

This is basically an evolution thread.  With a new idea that's 20 years old.  Here's the link  that started it.

 

The old idea's that organisms started having sex because mixing DNA would produce more mutations and we'd have wings.  Or something.

 

Anyway the "new" idea's the ancestral organisms started getting it on because (if I understand this right) if an individual gets stuck with too many bad mutations passed down to it it dies off.

 

Read the link for a better explanation.

 

The new work could help test a hypothesis first proposed nearly 20 years ago, stating that sex evolved as a way to purge harmful mutations from a population. According to this view, the random shuffling of genes through sex will sometimes have the effect of concentrating many harmful mutations into single individuals.

 

These individuals will be less healthy than their peers, and therefore more likely to be weeded out by natural selection, the thinking goes.

 

Now, assuming this works and it sounds reasonable - individuals with multiple negative mutations being "weeded out" - what's the implications in mankind's future where medical science has become advanced enough to save those negative epistasis(es?) and have them reasonably healthy and able to pass on their genes?

 

By the way, here's another bone to contemplate before closing:

 

"Most mutations are actually harmful, so anything that helps populations get rid of their harmful mutations is going to be important," Azevedo said. "The more interesting side of evolution is all the beneficial mutations that leads to complex structures, but the dirty work of evolution is to get rid of bad mutations, and that's where sex seems to play a role."

<{POST_SNAPBACK}>

The mixing of genes (crossovers and recombination) creates potential for individuals with collections of good copies of genes and bad copies of genes. There'll still be a bell-curve regarding the distribution of quality and number of mutations, of course, but creating individuals who can "concentrate" the mutations, as the article suggests, and getting rid of them, via natural selection, in a few generations, is beneficial to a group/population. (Not good for that individual. In a way, it's like death by a thousand pinpricks.) Deadly mutations will likely eliminate themselves quickly. However, if this theory is right, you can take less beneficial mutations and also clear the population of them.

 

With humankind, it might be a gradual spread of not-so-great mutations through the gene pool, but one has to also keep in mind there are several other mechanisms and barriers which are in place, like miscarriage or other health problems/disasters that might catch an individual before treatment is possible. Hard to say. Also, infectious diseases are always a reality, and those are another powerful arm of natural selection. Natural selection will never go away entirely. Increasing survival rates can lead to higher populations and more crowding, which would favor infectious disease and higher mortality rates.

[Azarkon]

There are no real, long term ramifications. Genetic diseases - at least those that manifest themselves physically or mentally - are normally unsavory to reproductive instincts. If medicine existed to counter their effects, the offspring of people with these genetic defects will become dependent on said medicine. Henceforth, if a catastrophe occurs and our technological infrastructure collapses, these people will die. But then for such a catastrophe to occur, many people will die anyways so essentially the gene pool will shrink and the "strong" will adapt while the "weak" will die off.

 

If such a catastrophe does not occur, we'll just become more and more dependent on our technology as a species. However, given that a society capable of warding off genetic diseases en masse likely has access to direct genetic manipulation, the accumulation of genetic defects really aren't something I'm all that worried about.

[Cantousent]

I love it when I read a post and get the feeling I've only understood half of it. I'm a bit slow. I do think it's interesting that, as a species, we're attracted to folks without rhyme or reason.

 

For instance, I've found a wide variety of women sexually attractive. Some of them were obvious choices, but others were not. Some of them became sexually attractive to me over time while others were attractive from the moment I met them. Some of them were pretty, but others were never what I considered pretty, even though I might have found them extremely hot. I can think of specific examples right now that fly in the face of conventional wisdom in terms of looking at sexual attraction.

 

I'm sorry. I know I'm giving a slightly different bent to the thread, but I find this idea of sexual attraction and how it plays in different people quite interesting.

[metadigital]

There are no real, long term ramifications.  Genetic diseases - at least those that manifest themselves physically or mentally - are normally unsavory to reproductive instincts.  If medicine existed to counter their effects, the offspring of people with these genetic defects will become dependent on said medicine.  Henceforth, if a catastrophe occurs and our technological infrastructure collapses, these people will die.  But then for such a catastrophe to occur, many people will die anyways so essentially the gene pool will shrink and the "strong" will adapt while the "weak" will die off. 

<{POST_SNAPBACK}>

You don't call a species becoming more dependent on artificial technology a real, long-term ramification?

If such a catastrophe does not occur, we'll just become more and more dependent on our technology as a species.  However, given that a society capable of warding off genetic diseases en masse likely has access to direct genetic manipulation, the accumulation of genetic defects really aren't something I'm all that worried about.

<{POST_SNAPBACK}>

Except that genetic manipulation can be prohibited by politics even when permissable by science. Maybe beyond the point of no return for said species.

[Azarkon]

You don't call a species becoming more dependent on artificial technology a real, long-term ramification? huh.gif

 

I thought that was a given? Seeing that the alternative - dying on average at ~20-25 - is not likely desirable, I fail to see how:

 

what's the implications in mankind's future where medical science has become advanced enough to save those negative epistasis(es?) and have them reasonably healthy and able to pass on their genes?

 

Should lead to any new causes for concern. Genetic manipulation is not likely to be prohibited in the case of correcting genetic defects such as that might result from the OP's concerns.

[metadigital]

1. People don't die at twenty without technology. Without knowledge, maybe, but not technology: farmers don't need super-growth fertilizers, they just give a higher yield.

 

2. You hope that genetic manipulation wouldn't be banned. Some religio-political systems don't agree with basic medical practices: Jehovah's Witnesses, for example, don't permit blood transfusions.

[Azarkon]

1. People don't die at twenty without technology. Without knowledge, maybe, but not technology: farmers don't need super-growth fertilizers, they just give a higher yield.

 

Fine, fine. Semantics and all that jargon. We're still dealing with the same thing here, because we already depend on technology, unless the argument is to reverse all the 'progress' we've made so far and return to primitivism.

 

2. You hope that genetic manipulation wouldn't be banned. Some religio-political systems don't agree with basic medical practices: Jehovah's Witnesses, for example, don't permit blood transfusions.

<{POST_SNAPBACK}>

 

Sure, but those organizations are just as likely to ban the practice outlined by the OP and, consequently, be potentially weeded out of the gene pool.

Edited March 7, 2006 by Azarkon

[Atreides]

Since this deals with genetics, here's news about a Turkish family that walks on all fours.

 

It's almost certain that there's something genetic going on - all 5 children have the same condition and it looks quite likely to be passed down.