Origins of Hutu, Tutsi and Twa of neighboring people, it was almost non-existent among Rwandan Tutsi. Presence of the sickle cell trait is evidence of survival in the presence of malaria over many centuries, suggesting differing origins. Regional studies of the ability to digest lactose are also supportive. The ability to digest lactose among adults is widespread only among desert-dwelling nomadic groups that have depended upon milk for millennia. Three quarters of the adult Tutsi of Rwanda and Burundi have a high ability to digest lactose, while only 5% of the adults of the neighboring Shi people of eastern Congo can. Among Hutu, one in three
History of Rwanda RPF control was occupied by France in Operation Turquoise. While the French operation did prevent mass killings it has been alleged that the deployment of French troops was intended to allow the Hutu militias to escape, and that the slaughter of Tutsis continued in the French controlled area. Between July and August 1994, Kagame's Tutsi-led RPF troops first entered Kigali and soon thereafter captured the rest of the country. The Tutsi rebels defeated the Hutu regime and ended the genocide, but approximately two million Hutu refugees - some who participated in the genocide and fearing Tutsi retribution - fled to