A gamma and G gamma globin chain synthesis in BFU-E colonies from adult, newborn, and fetal subjects and from thalassemic patients.

The G gamma and A gamma content of Hb F produced in cultures of BFU-Es from the blood of normal fetuses, neonates, and adults was determined. The results show that erythroid progenitors produce A gamma and G gamma chains in a ratio characteristic of their ontogenic stage. The analysis of the G gamma/A gamma ratio in culture of BRU-Es from thalassemic patients showed a marked heterogeneity, resembling that observed in freshly drawn cells. These results afford evidence that the type of gamma chain produced is programmed at the level of early erythroid progenitors.