As a person who knows next to nothing about how the brain or the genes that configure it work, I tend to think of this in terms of 80s video games like River Raid. The level data for these games, if stored naively, would fill the computer's available memory many times over. So they just store a pseudorandom number generator seed along with a few other parameters. Coupled with a few rules to make the level playable, it can generate a seemingly impossible number of levels with very little stored data.

Maybe the genes just encode a few crucial rules and the rest just emerge from that.

Oh, and I know even less about how the universe works. But I tend to think of it in the same terms: Emergent phenomena stemming from simple rules à la Game of Life.

Ever since I read about Rodney Brooks and his idea of the Subsumption architecture I've been convinced that something like this is going on in our minds - likely with some other mechanisms too. It just clicks for me - I'm mostly likely completely wrong, but it's a pretty cool idea, and I've used it to create some really interesting simulations.

https://en.wikipedia.org/wiki/Subsumption_architecture

That's mostly how I think of it, albeit the analogy I use is procedural texture or music generation in 4K demos.

There are very simple algorithms that generate (or maybe just expose) complex structures already "present" in the universe.