I think that this is a really excellent topic. There will have to be much in the way of research and analysis present here. In my mind, I feel that the most pressing difference between both sets of literature is the presence of race and how this factor helps in the social construction of identity. I would examine some of the writings of Henry Louis Gates, Jr. He has spent a great deal of time exploring the foundational elements of African- American literature. I think that your essay should spend some time assessing Gates' analysis and also delve into how race and identity are specifically powerful to African- American literature. It might be so important to the discussion of how it differs from traditional American Literature because what it means to be "different" is an element that is so unknown and so vast. The experience of being "different" is a part of the African- American literature dialogue specifically because it is not part of the dialogue of mainstream American Literature. While much of American Literature does discuss individuality and seeing things in a different light, African- American literature deals specifically with what happens when this is socially, economically, politically, and psychologically reinforced.