The story of Adam and Eve is a recast of an earlier Babylonian epic about Adapa. It is a retelling of how man lost the chance to dwell indefinitely on earth..
In the original story, Adapa did not even eat the fruit. But still lost the chance of immortality....
In the original tale, there was two different trees, the serpent of the tree of evil was Dimuzzi and the serpent of the good tree was Ninghiszida...

In my own opinion I think it is about making choices and facing up to the consequences...
Choice between life and death
Good and evil
Light and darkness
Hot and cold
Up and down
Long and short
Etc...