Ethidium bromide-stained gels (upper panels) and Southern blots (lower panels) showing expression by RT-PCR of HOX B6 in TER-119–separated 13.5-day fetal liver and adult bone marrow cells. From left to right-hand lane: markers; 13.5-day fetal liver TER-119⁻ population; 13.5-day fetal liver TER-119⁺ population; adult bone marrow TER-119⁻ population; and adult bone marrow TER-119⁺ population.