The Dos Santos family and their supporters claim they are the objects of political persecution.
The Khamas have dominated Botswana's politics since the 1870s, but they are now a discredited, spent force.
Gabon's strongman president, Ali Bongo, is barely clinging to power after contested elections, a stroke and a coup attempt. The Bongo family has run this stable central African nation for 52 years.
To reach the highest rungs of power, a new study shows, it really helps if your dad was president.