RATIO OF SICKLE-CELL ANEMIA HEMOGLOBIN TO NORMAL HEMOGLOBIN IN SICKLEMICS*

The erythrocytes of certain human individuals undergo a reversible change in shape known as sickling if deprived of oxygen (1, 2). Talia-ferro and Huck (3) postulated that this characteristic is transmitted by a single dominant gene, but failed to account genetically for the wide diver-gence in clinical signs and symptoms among individuals who possess sick-ling red cells. A small fraction, about 1 in 40, of these individuals have a severe chronic anemia called sickle-cell anemia; the others have no symp-toms which can be associated with this erythrocyte characteristic, and their condition is termed sickle-cell trait or sicklemia (4). Neel (5) has postulated that there exists in the Negro population a gene which in the heterozygous condition results in sicklemia and in the homozygous condi-tion in sickle-cell anemia. His statement is based on the finding that the trait was present in every parent of a sickle-cell anemia patient that he tested. This hypothesis is in accord with the results of recent electro-phoretic studies of the hemoglobins in these conditions (6, 7). Thes