Genera core

the core things around which a genera is built.
the reason the genera exists is because people who read or watch this genera want to see the genera core items.
if you write in a genera the story must feature some of the genera core items or the audience will be disappointed, even if the story contains materiel that would be appreciated in another genera.
people pick up a genera book because they seek the genera core items.
in a western the genera core items include action, manly guys in hats, horses, the west.
in a mystery the genera core items include murder, a person intentionally trying to find the murderer and motive, a murderer with a motive.