Hi Xstar, welcome to EvC.
I am new to these boards, so forgive me if this has already been asked.
I'm new myself, but you get used to the place after reading the threads for a week or two. You'll figure out what has and has not been discussed or mentioned or explained.
I have searched high and low to find any evidence supporting a beneficial mutation. All I have ever seen is mutations where it seems as though it would hinder the creature, not help it.
There have been specific experiments designed to induce a beneficial mutation in bacteria; a bacterium that was known not to possess any capability of lactose metabolism was cloned, and placed in a medium that selected for precisely that metabolism. After a few thousand generations, the majority of the population had developed it.
The only way that ability could have arisen was through mutation. And since it clearly increases the ability of that organism to survive, it is beneficial.
This in particular was described in a recently active thread, somewhere in this forum as well. You might be able to find it; pay special attention to posts by Wounded King explaining the matter to us others.
Also, I have never seen any evidence of a creature gaining anything new, which be required for the evolution theory. This really makes me question evolution, since it's based completely off mutations.
Nylon-eating bacteria and
oil-eating bacteria are two clear examples of a new trait developing. Then there's
these beneficial mutations which provide a definite advantage to survival; the CCR5 delta32 for example meant a higher probability of getting through plague or serious infection. Then there's plenty of evidence in the fossil record and in genetics for the existence of them.
When it comes to it, only a minority of mutations actually have any effect.
A majority of them are neutral; something like 70% don't actually change the protein structure in any meaningful way and so they aren't selected for or against. Of the rest, quite a few are obviously bad. They kill the organism no matter what, so they're definitely harmful and for this reason harmful mutations are simply more likely than beneficial ones. But for many, it's about context: what's good for one thing in one place might be bad for another or in another place.
So, when all things are considered, there's plenty of evidence for this part of evolution, and for evolution in general.