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
Rwandan genocide the capital and the country. An estimated 2,000,000 Rwandans, mostly Hutu, were displaced and became refugees. The genocide was planned by members of the core Hutu political elite, many of whom occupied positions at top levels of the national government. Perpetrators came from the Rwandan army, the Gendarmerie, and government-backed militias including the "Interahamwe" and "Impuzamugambi". The genocide took place in the context of the Rwandan Civil War, a conflict beginning in 1990 between the Hutu-led government and the Rwandan Patriotic Front (RPF). The latter was made up largely of Tutsi refugees whose families had fled to Uganda after the