The prefix sub- means "under," or "lesser." A sub-genre is a genre within a genre, that is a specific category within a more general one. For example, within the genre of Juvenalia, or "children's literature," a sub-genre might be books specifically intended for pre-teen boys.
the genre is children's literature
genre...?
Another genre (distinctive type of writing in literature) is the short story.
The Battle of Dorking is credited with starting the invasion genre of literature
british literature
Children's Literature
Literature
The best books in a genre
The best books in a genre
Children's literature
The genre of Car Trouble is young adult literature.