Wizards have no potential in mutations

[Sord213]

I was playing as a wizard on gibbed 4 today and i got to be a wizard... so i got genetics to scan me and he told me i had nothing at all,weird isn't it?

I'm guessing if you're looking for some canon reason it's probably wizards go through extensive training in order to use magic, but everyone's born pretty much with ability to.

and on the same time i found that a cyborg can live without a head if you destroy it with a C-saber somewhy

The brain (you know that part that's used to make the cyborg actually live) is stored in the head. Ripping out the brain from a computer tends to disable it.