QUOTE (Lady Otterwynnd @ May 10 2008, 07:39 PM)

Oops, guess we do have positive mutations, eh? As everyone has been saying, most mutations are not passed on to the next generation because of natural selection. Got it? If they are passed on it's because the trait is recessive, or that organism is benefited by the mutation. If the mutation is negative, the organism dies (most of the time). Humans are an exception because we treat and take care of people who have life threatening mutations. If we didn't care for them and support them with technology they would die and the mutations wouldn't be passed on as frequently.
QUOTE (Doug1o29 @ May 10 2008, 12:51 PM)

Guess again. EVERY beneficial (contributing to reproductive success) gene that now exists in humans was the result of a mutation.
Period. That's millions of positive results of mutations, just to keep your body functioning.
You seem to have a mind-set that says mutations are bad. They're neither good nor bad - they just are. In nature, there is no good or bad; things just exist and do stuff. They either work or they don't. Nature does not make value-judgements.
Doug
QUOTE (churchanddestroy @ May 10 2008, 04:18 PM)

No body is saying that mutations are "good" or "bad". Some mutations have benefits, and some mutations are detrimental, but they aren't "good" or "bad" things. Mutations are just mutations.
QUOTE (Leonardo @ May 10 2008, 05:05 PM)

I like how you twist the wording of the article to suit your agenda, WWF.
No one here has stated there are not 'negative' mutations. The disagreement is your lumping the negative in with the neutral and saying "by far most mutations are negative or neutral" when saying "by far most mutations are positive or neutral" is just as true - because neutral mutations outweigh neavily both the negative and positive mutations combined.
Your disingenuity does your credence as someone who follows the tenets of a religion that frowns upon dishonesty no favours whatsoever.
No comment on this positive mutation of sickle cell trait though?
I applaud your efforts, but a closed mind is like a house with its windows and its doors barred and guarded. I think for you guys to communicate what you are trying to communicate to him you have to back pedal through so much biology that the task would daunting.
Also, I would like to point something out for those with a basic grasp on this stuff, but maybe slightly confused on the prorogation of negative mutations.
We saw with the example cystic fibrosis that the increase to frequency in the population was due to resistance to tuberculosis. So this is a case of a "bad" mutation, that once had a "good" benefit to individuals (the fact of how wide spread carriers are attests to the success of genotype).
But how are other "negative" mutations maintained in a population which seemingly incur no benefit?
As we have been talking about the beneficialness of a mutation is contextual. To not only the environment in which it arises, but the
specific genome in which it arises. Let's use a hypothetical example to illustrate this. Let's pretend we have some make-believe organism, which have sequenced its entire genome. We find that it has a mutation that
we consider negative for some reason or another. But amazingly the frequency of this "bad" gene is extremely high in the population. How could such a thing occur?
We need to not be so narrow in our view (as some would like to have it regarding mutations). Since we have the genome sequenced of our make-believe organism, lets say we started looking at other genes. And we find, a gene close by that has, low and behold, a great benefit to the organisms fitness, Much greater than the damage done by our "bad" mutation! Because the location of the "bad" gene and the genome in which it exists, it gets a "free ride" to higher frequency in the population.
This is important in evolution. Now we have a gene that in the current environment may seem "negative" -but what happens when the environment changes?
Remember, Selection works on various levels. We can think of selection working on the molecular, gene, genome, cell, organism, family group, community, population and species level.