DNA contents of parental and progeny clones. Procyclic trypanosomes were stained with propidium iodide and the peak intensity of red fluorescence was measured by flow cytometry. All values were normalized relative to T. b. brucei 427, which was included in each run. DNA contents of individual clones (diamonds) are plotted on an arbitrary scale relative to the DNA content of T. b. brucei 427 = 1.0 (dotted line). The two parental clones, J10 and 1738, and four F1 clones are indicated; all have slightly lower DNA contents than the standard, T. b. brucei 427.