Do you have memory and knowledge of everything in your DNA and what problems it will cause in your body in future?
How you ended up with that particular combination of DNA?
DNA was there long before anyone had known about. It didn't just turn up when scientists found out about it.
Did people know which defects in their DNA their bodies were being punished for?
We will all be punished one way or the other during our lives.
Why don't we know in advance what sort of lives we will go through?
Why can't science tell us from the moment a baby is born, everything it will go through in its life?
Does science not exist if it can't tell you that?
As a very broad generalisation, you can consider Karma to be the DNA of the soul.
Not having knowledge or memory of it doesn't necessarily mean it is not there.
The soul is the same, in the previous life, in this life and in the next life.
The soul carries its Karma balance from one life to the other.
As it advances spiritually, it will get memory and knowledge of its Karma and will be able to get rid of the remaining balance, achieving 'Nirvana', another concept very badly misunderstood outside the cultures that have believed in it for a long time.