Size distribution of the RPCI-11 library. A total of 483, 246, 299, 308, and 212 clones from each of segments 1–5 was picked randomly and analyzed with a CHEF apparatus after NotI digestion. The horizontal axis refers to the size range of insert DNA, and the vertical axis indicates percentage of clones corresponding to each size range. Purple, pink, yellow, blue, and green bars correspond to segment 1, 2, 3, 4, and 5, respectively.