Characterization of the giant panda BAC library. A. Analysis of the size of BAC clones by PFG electrophoresis. M: Mid range Marker II for PFGE (Bio-labs, New England). Lanes 1–19: Not I digested DNA of randomly picked recombinant BAC clones. PFGE conditions were set with Bio-rad CHEF III: 6.0 v/cm for 12 h, linear pulse time ramping from 0.1 to 40 s. B. BAC insert size distribution in the library. Insert sizes were determined from 261 BAC clones. The horizontal axis shows the size range in kb while the vertical axis displays the number of clones corresponding to each size range. Insert sizes are reported in a cumulative histogram.