PCR analysis for the presence of donor-specific Y-chromosome sequence in splenic colonies. A small fragment of each colony was subjected to PCR analysis to detect the presence of the SRY sequence. Representative results using G-CSF concentrations of 25 or 50 μg/kg/d are shown. At 25 μg/kg/d, all colonies were positive for SRY (lanes 1 through 4), whereas only 2 colonies (lanes 7 and 9) were positive at 50 μg/kg/d (lanes 5 through 11). β-Actin used as an internal control was positive in all samples. (♂) Male, (♀) female, and (M) marker DNAs.