Hemoglobin ontogenesis: test of the gene excision hypothesis.

The gene excision hypothesis of hemoglobin ontogenesis was tested in persons with HbSC disease, with the use of monospecific fluorescent antibodies for the identification of hemoglobins S, C, and F in individual erythrocytes. The results are incompatible with the prediction that only one gamma- or beta-globin gene may be active in any single chromosome and provide further evidence for incomplete repression of gamma-globin genes lying cis to active beta-globin genes.