Origins of Hutu, Tutsi and Twa adults has a high capacity for lactose digestion, a surprisingly high number for an agrarian people, which Mamdani suggests may be the result of centuries of intermarriage with Tutsi. Bethwell Ogot in the 1988 UNESCO "General History" further notes that the number of pastoralists in Rwanda increased sharply around the fifteenth century. Although Luis et al. (2004) in a more general study on bi-allelic markers in many African countries found a statistically significant genetic difference between Tutsi and Hutu, the overall difference were not large. Modern-day genetic studies of the Y-chromosome generally indicate that the Tutsi, like the Hutu, are
Rwandan genocide magazine called "Kangura", which became popular throughout the country. This published anti-Tutsi propaganda, including the Hutu Ten Commandments, an explicit set of racist guidelines, including labelling Hutu who married Tutsi as "traitors". In 1992, the hardliners created the Coalition for the Defence of the Republic (CDR) party, which was linked to the ruling party but more right wing, and promoted an agenda critical of the president's alleged "softness" with the RPF. Following the 1992 ceasefire agreement, a number of the extremists in the Rwandan government and army began actively plotting against the president, worried about the possibility of Tutsi being