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
Tutsi closely related to each other than to faraway groups. There are essentially two groups of Tutsi in the Congo (DRC). There is the Banyamulenge that live in the southern tip of South Kivu. They are descendants of migrating Rwandan, Burundian and Tanzanian pastoralists. And secondly there are Tutsi in North Kivu and Kalehe in South Kivu - being part of the Banyarwanda (Hutu and Tutsi) community. These are not Banyamulenge. Some of these Banyarwanda are descendants of people that lived long before colonial rule in Rutshuru - on what's currently Congolese territory. Others migrated or were "transplanted" by the Belgian