Why would it be assumed that innate behaviors were coded somethere in DNA?

Innate behaviors are typically considered to be hardwired and consistent across individuals of a species, suggesting a biological basis. Since they arise without prior experience or learning, it implies a genetic component that influences behavior. Evolutionary pressures may have favored certain behaviors that enhance survival and reproduction, leading to their encoding in DNA. Thus, the assumption is that specific genes may regulate the development of neural circuits that produce these innate behaviors.