The relative gene expression of HOX B6 compared with HPRT during murine development. (Upper panel) Graphical representation showing the relative band intensity (in arbitrary units) against day of development. The single line shows the mean of all HPRT values. (Lower panel) Ethidium bromide gels for HOX B6 and HPRT from which the graph was obtained. Lane 1, markers; lane 2, 6.5 days; lane 3, 7.5 days; lane 4, 8.5 days; lane 5, 9.5 days; lane 6, 10.5 days; lane 7, 11.5 days; lane 8, 12.5 days; lane 9, 13.5 days; lane 10, 14.5 days; lane 11, 15.5 days; lane 12, markers; lane 13, 16.5 days; lane 14, 17.5 days; lane 15, 18.5 days; lane 16, 19.5 days; and lane 17, 0.5-day neonate.