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
Islam in Rwanda the Rwandan Genocide of 1994, Muslims were held in low regard, because they were seen as traders, in a land where farmers are highly regarded. The Muslim population before the genocide was 4% which was unusually low compared to that of neighbouring countries. Muslims were also affected by the genocide. There were only a few incidents in which Tutsis in mosques were attacked. The most widely known example occurred at Nyamirambo Main Mosque, where hundreds of Tutsi had gathered to take refuge. The refugees in the mosque fought off Hutu militias with stones, bows and arrows, putting up stiff resistance