Ethidium bromide gels (A and C) and Southern blots (B and D) for HOX B6 and EPO compared with HPRT control gene expression (E) in different tissues and organs during murine development. Lane 1, markers; lane 2, 6.5-day embryo; lane 3, 7.5-day embryo; lane 4, 8.5-day embryo; lane 5, 9.5-day embryo; lane 6, 10.5-day embryo; lane 7, 11.5-day embryo; lane 8, 12.5-day fetal liver; lane 9, 13.5-day fetal liver; lane 10, 14.5-day fetal liver; lane 11, 15.5-day fetal liver; lane 12, markers; lane 13, 16.5-day fetal liver; lane 14, 17.5-day fetal liver; lane 15, 17.5-day fetal spleen; lane 16, 18.5-day fetal liver; lane 17, 18.5-day fetal spleen; lane 18, 19.5-day fetal liver; and lane 19, 0.5-day liver.