Evidence for the clonal nature of erythropoietic bursts: application of an in situ method for demonstrating centromeric heterochromatin in plasma cultures.

Erythropoietic bursts were produced in plasma cultures seeded with a mixture of male and female murine bone marrow cells. Chromosome spreads of C-metaphases were prepared and stained in situ with a modification of the C-banding technique. In cultures seeded with mixtures of male and female cells, homogeneity of male or female C-metaphases in erythropoietic bursts was established by the presence or absence of the Y-chromosome. These results provide evidence that each erythropoietic burst is a clone, and that the erythropoietic burst-forming unit (BFU-E) is a single cell.