What are people under the impression DNA affects if not intelligence...?

Preface: I haven't seen this movie yet, but I watched the trailer to see if I might be interested, and...

The trailer for this movie even starts off with a narrator saying: "In the not too distant future, our DNA will determine everything about us. ... A single drop of blood determines where you can work ... what you're capable of achieving."

Umm, yeah, that's called reality.

Your genetic makeup massively influences your intelligence, personality traits, talents, and so on. I mean, what are people under the impression that DNA even does if not code for myriad proteins that influence everything that goes on in our brain? Do people seriously think the brain just randomly rolls the dice and your intelligence and personality traits and talents are all completely random?

If not, are people instead under the impression that it requires no more intelligence to be a petroleum engineer than it does to be a janitor? Or that pretty much everyone is intelligent/talented enough to do anything?

I have a feeling this movie would irritate me more than entertain me...