examination of the time course of colony formation , and the ultimate size and lineages represented in colonies produced in semisolid medium containing methylcellulose , together with analysis of individual erythroid colonies stained with rabbit antisera specific for adult ( hba ) and embryonic ( hbe ) mouse hemoglobins , revealed the presence on days 7 and 8 of gestation ( but not later ) of erythropoietic progenitors that give rise to mature erythroid colonies containing up to 100 hbe-containing erythroblasts after 4-6 days of growth in culture .
C0019016
hba
C0019046
hemoglobins