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
Tutsi Since Burundi's independence, more extremist Tutsi came to power and oppressed the Hutus, especially those who were educated. Their actions led to the deaths of up to 200,000 Hutus. Overt discrimination from the colonial period was continued by different Rwandan and Burundian governments, including identity cards that distinguished Tutsi and Hutu. In 1993, Burundi's first democratically elected president, Melchior Ndadaye, a Hutu, was assassinated by Tutsi officers, as was the person entitled to succeed him under the constitution. This sparked a genocide in Burundi between Hutu political structures and the Tutsi military, in which "possibly as many as 25,000 Tutsi"