I personally don't think that there is a "preparedness gene," at least the well-rounded preparedness the way we think of the term. Some might argue that females have that maternal instinct to care for her young or that vague "nesting instinct". I think personal experiences and your parents' attitudes are primarily responsible for whether we grow up being preparedness-minded, whether postively or negatively reinforcing it. For example, you might have had totally un-prepared parents and have vivid memories of some childhood event and that has caused you to be the opposite.

However, when it comes to particular traits, whether it's the hoarding of supplies or the stockpiling of weapons that goes along with some sense of paranoia, I could believe that there is a genetic component to those traits.