Numbers of lineages generated by sibling cells taken from 4 to 8 cell colony starts.

Colony starts were initiated from unseparated marrow (BM; total, 15 starts), marrow cells after overnight selection in thymidine (TdR; total, 28 starts), or the rhodamine 123^loLy6A/E^hi marrow cell fraction (total, 54 starts). Left-hand panels indicate the relative frequencies at which colony starts displayed single or multiple lineage potential. For example, after thymidine selection, 58% of the colony starts displayed the potential to differentiate into 2 lineages. Right-hand panels indicate the relative proportions of starts whose siblings all yielded the same kind of colony, as a function of the total number of lineages found in the colonies. For example, after thymidine selection, daughter cells from 63% of bipotent colony starts had identical bilineage outcomes after individual culture, whereas 37% of starts yielded secondary colonies that did not have identical outcomes. In the lower-right panel, lightly shaded bars represent secondary colonies that were identical. A lower level of stringency, in which one sibling subclone with a disparate outcome was allowed, is represented by darkly shaded bars.