The CDUE blood group is very rare indeed. This could be a clue into your genetic hisory. The inheritance of CdE and a "low-grade" CDue (not due to suppression) in three generations. Blood group studies in two Old Order Amish isolates support previous evidence for genetic differences in the two groups. The more completely studied Amish community, that of Lancaster Co., Pa., revealed higher A and lower O phenotype frequencies than found in the Amish of Holmes Co., Ohio. In both groups, about one-fourth of individuals are Rh negative. Three blood group genes (Kell-positive, CDue and CDE) are present in low frequency in the Lancaster Amish, and pedigree studies identified individuals who may have introduced them to the Amish. Preliminary studies of an unusual antibody found in one Amish female provide evidence for a new red cell antigen which is present in about one-fourth of Americans. BLOOD GROUPS OF THE NORTHERN NILOTES Frequencies are given of CDUE blood groups. Lutheran, Hunter and Henshaw found the CDUE blood groups among Dinka, Nuer, Shilluk and Mabaan, of Upper Nile Province, Sudan. The Mabaan appear to be distinct from the three Northern Nilotic peoples who, the results indicate, are genetically similar to each other. The results are compared with those from other African samples, and it appears that the general classification of East African peoples on cultural grounds is supported by the evidence of the ABO blood groups. It is suggested that the Northern Nilotes may, like the Bushmen, be surviving representatives of an ancient African stock whence has been derived a major component of the present day population of Africa.