Why so many disorders in children?

[CraigD]

Originally Posted by Back2Reality

The point was that we are accumulating more and more genes for disease in our gene pool and that eventually everyone will be born with serious defects. Everyone requiring surgery right from birth and medical dependency is not insignificant - it is a nightmare.

Though a real concern for public health, this scenario assumes that selection due to juvenile mortality is the only factor involved in the inheritance of genes. However, other factors, such as gene dominance/recessivity, also play a role, as do social factors, such as people with heritable diseases choosing not to or being prohibited from having children.

Another very real possibility is that the coming decades will see continuing advances in medicine and genetics, allowing genetic defects to be routinely and permanently detected and corrected prior to birth.

Last, it’s worth noting that a larger, sicker gene pool is not necessarily bad, from an evolutionary biological perspective. Although increasingly effective medical techniques allow more disease-related genes to remain in the gene pool, a larger, less selected population has greater genetic diversity. Natural history hold many stories of species which, subjected to strong selection pressure (eg: environmental/habitat/competitor stress), settled into a more optimal but less diverse gene pool, sometime even speciating, then later proving unable to adapt to changing conditions, and becoming extinct.

[Back2Reality]

Originally Posted by CraigD

Though a real concern for public health, this scenario assumes that selection due to juvenile mortality is the only factor involved in the inheritance of genes. However, other factors, such as gene dominance/recessivity, also play a role, as do social factors, such as people with heritable diseases choosing not to or being prohibited from having children.

Another very real possibility is that the coming decades will see continuing advances in medicine and genetics, allowing genetic defects to be routinely and permanently detected and corrected prior to birth.

Last, it’s worth noting that a larger, sicker gene pool is not necessarily bad, from an evolutionary biological perspective. Although increasingly effective medical techniques allow more disease-related genes to remain in the gene pool, a larger, less selected population has greater genetic diversity. Natural history hold many stories of species which, subjected to strong selection pressure (eg: environmental/habitat/competitor stress), settled into a more optimal but less diverse gene pool, sometime even speciating, then later proving unable to adapt to changing conditions, and becoming extinct.

A larger sicker gene pool is certainly bad. You are correct about the usefulness of a degree of variation, in order for a small change not to wipe out an entire species, but the variation in genes will have to be healthy genes.
The vast majority of all mutations are fatal. The few that are not have the potential to be selected favourably should they assist survival.
Some, very few useful genes can also have a dual effect of causing a disease. But the vast majority of harmful genetic defects can never have a "good" side under any circumstances so we should not be trying to get as much deformity and weakness into our population as we can expecting that this "mutational overload" will lead to our long term survival as a species!

[HappytheStripper]

One question I would like to ask is .. Why so many children live within an environment of dis-order.. ??

I remember as a teenager telling me mother.. I thought she put me together backwards.. I reasoned this as I was a by-product of disorder born into chaos..

Ashley

[KickAssClown]

Originally Posted by Back2Reality

I didn't say natural selection was stopped, I said that civilization limits the extent that natural selection can keep the population healthy. Once you start preserving the lives of people born with heart defects for eg you allow the genes for defective hearts to spread into the population. But there are thousands more such defects being perpetuated and spread. It is doubtful any of us are as healthy genetically as we would have been with normal natural selection pre-civilisation at play. In nature, every living creature is supposed to produce an excess of offspring - often hugely in excess - of what will eventually survive. What does survive is exceptionally healthy as well as lucky.

Well that is somewhat false. "Natural selection" is not slowed, nor stopped by artifical developments. We can't fence it in or out. Where ever life is, and reproduces so follows "natural" selection.

The only thing that changes is environment. Now your talking about healthy and fit and things like that and what you have to realize is that if the creature is surviving and reproducing then it is healthy enough to propagate it's genes. Now this is actually not natural selection, this is an individual case.

What "natural" selection is most relevant to is population demographics of reproduction in relation to a given eco system.

What is "fit" or "healthy" is whatever allows the population to propagate it's genes in it's eco system. Now if the eco system changes then what was fit could become unfit for the new eco system.

This of course is quite a bit less than what you could learn from cracking an evolutionary biology book with a good comprehension of statistics under your belt.

The thing is, while, yes, some genes will get mixed around that might be maladaptive, those same genes are going to "select" themselves out over generations, even if we don't necessarily artifically select them out ourselves, assuming of course that those genes are infact defective.

It has to do with statistical probability. A less healthy population (within relation to their environment) will die out over generations, because they will not breed as much as a healthy population.

Warning & Disclaimer: I do not mean to be offensive, this is merely a relay of what I percieve to be factual observation, and is not intended to be taken out of context.

The example I would most readily give is those with severe retardation. Particularly of the mental and/or developmental kind. Though, yes, they do breed to a small degree, the fact is that on average over the entire population, the sub-replacement rate of that particular population is a regulating (see Negative Feedback) pattern. They do not reproduce over multipul generations. That is what is important to "natural" selection.

Consistent reproduction over multiple (tens, hundreds, thousands) of generations.
If the population underconsideration does not reproduce in greater than the sub-replacement rate, they die off or meet equilibrium (stable population for a given eco system).

If they reproduce in greater than the sub-replacement rate then the population grows to meet equilibrium (Once again stable population for a given eco system).

I hope that wasn't too much information.

[ErlyRisa]

Girls are having thier first period later - boys ar boys for alot longer, especially mother's boys.

--the overall societal impact? - children are having children!!!!

children are trying to raise children!!!!....

have a look at the way society is based... it's quite comfortable... the old 'survival' instincts of daily life have dissipated. We as apparent adults are raising children which in effect will be even more child like. -it all started with the babyboomers parents, and will end with GenZ - don't worry the apperent spike won't last forever.

-these spikes in history have come before in all of the civilisations.


guess who our parent is? -the media....

want a cure? throw out ur TV. PS your neighbour has to throw it out to!

--an intersting study would be to have a look at the Shaker society, what are thier kids turning out like?... id disease as rampant?

---the West, as an organism itslef is suffereing from Autism... it may be able to 'calculate' faster, but as for some other traits....some of them will never be learnt, untill we reach adulthood(genZ)

[swampfox]

Guess I got another one: So I'm flippin' the channels and get to MTV, something I used to like to watch. The subject was "springbreak nightmares": Apparently, girls going to spring break is a lesson in extreme dieting! Way to go guys. Wonder why? Tell you what, I don't want another daughter; don't want to go through the heartbreak of watching another one grow up. Good luck with um' guys. You having problems with them, start a thread and if I see it I'll try to contribute.