Figure 3.
More active human L1 elements produce longer insertions in HeLa cells. Plotted are the percentages of G418R HeLa clones that are positive for the 2 kb ruler PCR (dark bars) or the 3 kb ruler PCR (light bars) for each of the five wild-type human L1 elements. Shown below the graph are the nRFs, using the retrotransposition frequency of the least active element, L1.2A as a basis for comparison. The absolute retrotransposition frequency for L1.2A in this experiment was 1/838. The following numbers of clones were typed for each element: LRE3 (94 clones), L1RP (46 clones), L1.2B (19 clones), L1.3 (31 clones) and L1.2A (54 clones). All 244 clones were positive in the 1 kb ruler PCR.