DNA is what codes for everything in your body and DNA helps make proteins mRNA tRNA and rRNA
Innate behavior is very often considered to be th eresult and a consequence of learning which was done in the earliest stages of life; womb, infancy up to childhood possibly. Most of the time, this learning has to either be model learning of reinforcement learning where the organism or child, if we're talking about human beings, get feedback once they do something; either negative - diminishes the behavior, or positive - increases it.
The nucleus contains the cells DNA(genetic material) which is basically the recipe for making proteins. mRNA is first transcribed off of DNA and then in translated(by ribosomes) to polypeptides(proteins).