Some of the key findings are that most African-Americans have roots in Angola and the Democratic Republic of the Congo. There is also an over-representation of Nigerian ancestry in the United States and Latin America. Also, there are less who descend from Senegal and The Gambia, one of the first regions where slaves came from. This is largely due to the fact that many were sent to work in really dangerous conditions. One other key discovery is the impact that there are stronger contributions made by females to the gene pool even though the majority of slaves were male. This is likely due to rape and other forms of sexual exploitation.
This study is a pretty grim one, but also a fascinating one at the same time. I think what has to be hard for African-Americans is not knowing for sure who their ancestors were and/or where they come from. Hopefully this study and future ones can help them feel more connected to their African roots.