system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5, how instinctive knowledge and behaviour is passed through genes, as opposed to learnt behaviour. Eg. A kitten is put into isolation from day one, yet still scuffs at the floor when pooping.
gpt
Brains develop, much like all organs, from the control of genes. During development, neurons use various methods of signalling to "make" certain parts of the brain essesntially "hard-wired" for a behavioural tendency, which in turn can ~~illicit~~ elicit *(too much crime reading haha, thank you!)* a physiological response, eg. sexual arousal, wincing at a bright light, scuffing at the floor if you're a cat or a weird human. 
There is a high degree of genetic regulation in neural development, it'd be wild if many behaviours weren't hereditary.