Final answer:
The 18th and 19th centuries saw African American writers primarily contribute to the genre of autobiography and narrative, with works by Olaudah Equiano and Frederick Douglass, and later, Booker T. Washington. A diversification of genres occurred post-Civil War into Southern gothic led by wider Southern literature movements. The Harlem Renaissance marked a significant evolution with writers focusing on African-American heritage and experiences.
Step-by-step explanation:
The dominant genre of African American writers in the 18th and 19th centuries was not uniform, but a significant contribution was made in the realm of autobiography and narrative. The early works by African American authors like Olaudah Equiano and Frederick Douglass centered on autobiographical accounts of slavery and freedom. This tradition continued with key figures like Booker T. Washington, whose work Up from Slavery is considered an important narrative and autobiography contributing to African American literary culture and providing social commentary.
By the late 19th century, African American literature began to move towards more diverse genres and styles. The post-Civil War era, sometimes referred to as the Southern Renaissance, saw Southern writers delve into Local Color and examine edgy topics including the critique of traditional social roles and the exploration of repressed sexuality. Writers from this period contributed to the emergence of the Southern gothic genre, focusing on the grotesque, and Southern dialects. While not exclusively African American, this setting provided a backdrop for African American writers to explore pertinent themes.