Sorting and analysis of retrovirally transduced ASMKO bone marrow cells. PCR analysis and ASM enzyme assays were conducted in triplicate on sorted B12^low and B12^high cells from the Lin⁻/FSC^low/c-Kit⁺population (left; stem cell–enriched) and Lin⁻/FSC^high/c-Kit⁺ population (right; progenitor cell–enriched) as described in the text. ND, not detected. The experiment was repeated three times, and the representative data from one experiment are shown.