I have 2 theories, i think that the fruit contained gods DNA, now making us half god and half animal,explaining why we have souls and are so much smarter than all the other animals or I think that the fruit is irrelevant, its the fact that it was forbidden by god and It was the choice that was the problem, because before that they hadn't committed any sin or disobeyed god or ( knew evil ) but as soon as eve disobeyed God, at that point they then learned that it was possible to disobey god therefor opening their eyes to evil and good.