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
1996 Burundian coup d'état first democratic presidential election on 27 June 1993, which was won by Hutu Melchior Ndadaye. On 21 October, Ndadaye was assassinated, sparking the Burundi Civil War between Hutu and Tutsi groups. Moderate Hutu Cyprien Ntaryamira became president in February 1994, but both he and Rwandan president Juvénal Habyarimana were assassinated in April that year, an event that sparked the Rwandan Genocide. Ntaryamira was succeeded by another Hutu leader, Sylvestre Ntibantunganya. On 21 July 1996, Hutu rebels attacked a refugee camp in the country and killed more than 300 people. On 23 July, President Ntibantunganya went into hiding at the home