How Does a Genome Give Rise to Intelligence?

Our genome is, as you say, about three billion base pairs each. So that's relatively small compared to the complexity of a neural circuit. A human brain has about a hundred billion nurons. That's potentially a hundred billion squared zeros. And onest if you allowed any arbitrary circuit to be expressed, and that clearly cannot be expressed explicitly in a genom. But there are so many things that all organisms, even humans, can do with little or no experience. The wiring diagram in a normal machine learning setting is absorbed somehow through experience. We don't learn n primarily in a supervised fashion.