How have conditions and events in the Dominican Republic shaped the characters' lives in The Brief Wondrous Life of Oscar Wao?

Since many of the characters in Junot Diaz's Brief Wondrous Life of Oscar Wao are themselves Dominican, they and the narrator often reference life, culture, and history on the island. Diaz expects his readers to have little knowledge of the Dominican Republic and will frequently go into very great detail throughout the footnotes (which are unusual in a work of fiction).
Perhaps the most frequently mentioned name in the book, besides that of Oscar himself, is that of the dictator Rafael Trujillo, who controlled the DR with an iron fist from 1930 to 1961. Trujillo controlled the media, the police, and the military: Diaz often compares him to twentieth-century dictators like Adolf Hitler, Benito Mussolini, and Josef Stalin to impress upon the reader how great an impact Trujillo had on the DR. While Oscar's story takes place decades after Trujillo's death, the characters and the narrator often refer to Trujillo—as a specter, as a reminder of their past, or simply to strike fear into naughty children. Trujillo imprisoned and tortured Oscar's grandfather, as he did so many thousands of other Dominicans, directly linking the history of the DR with Oscar himself. Throughout the story we hear Trujillo's name mentioned casually and mentioned in fear. A reader will also learn many anecdotes about his misrule, including the fact that the mass deforestation in Haiti did not occur in the DR, because Trujillo made the forests his personal property and refused to let outsiders in.
Other tidbits about Dominican culture are peppered throughout the novel. For example, the footnote on page 87 tells the story of Maria Montez, a Dominican actress who became famous in American golden-age cinema. The footnote on page 215 tells the story of Oscar's family at the time of the 1937 massacres against Haitians living on the border. Spanish slang terms, many of which are impolite, are littered throughout the story.
Oscar himself returns to the Dominican towards the end of the story and finds that he cannot connect to the culture: he cannot dance salsa, he has no machismo confidence, and he feels that he cannot fit in with his extended family. He falls in love with a prostitute, only to be killed by her boyfriend and his band of thugs.