Origins of Hutu, Tutsi and Twa phenotype, genotype, cultural memory of inhabitants of Rwanda, archeology, and linguistics. Most Tutsis and Hutus carry the E1b1a paternal haplogroup, which is common among Bantu populations. More recent studies have de-emphasized physical appearance, such as height and nose width, in favor of examining blood factors, the presence of the sickle cell trait, lactose intolerance in adults, and other genotype expressions. Excoffier et al. (1987) found that the Tutsi and Hima, despite being surrounded by Bantu populations, are "closer genetically to Cushites and Ethiosemites". Another study concluded that, while the sickle cell trait among the Rwandan Hutu was comparable to that
Burundi some Hutu felt this was unjust and ethnic tensions were further increased. In October 1965, an attempted coup d'état led by the Hutu-dominated police was carried out but failed. The Tutsi dominated army, then led by Tutsi officer Captain Michel Micombero purged Hutu from their ranks and carried out reprisal attacks which ultimately claimed the lives of up to 5,000 people in a precursor to the 1972 Burundian Genocide. King Mwambutsa, who had fled the country during the October coup of 1965, was deposed by a coup in July 1966 and his teenage son, Prince Ntare V, claimed the throne.