system
Given the following post, respond as if you're commenting on Reddit:
human
How can DNA code for instinctive behaviours such as building nests, recognising preys, finding the mother's breast...?

Or how can DNA code for a brain with basic programmed behaviours?
gpt
DNA doesn’t code for any “behavior”, just proteins that make up cells. Some (all? Not a devo biologist here) basic instincts, babies grasping a finger in their palm, for instance, are reflexes. The DNA codes for the proteins that guide the formation of neurons in that reflex pathway through the central nervous system. Other behaviors are learned from a young age. Neuroplasticity refers to the ability of the brain to reprogram itself, and young things have very neuroplastic brains. Through this neuroplasticity, young animals can quickly pick up on the behaviors that keep them alive. This process is imperfect and the animals that don’t do this will die. 

TLDR, the DNA doesn’t encode behavior, but it can encode reflexes via neuron development.

Hope this helps!