Figure 3.

Quantification of L1Hs-Ta 3′ UTRs in the human genome. Southern blot quantification. Genomic DNA from (1) individual Ca-2, (2) mouse LMTK-cells, and (3) LMTK-cells to which plasmid pL1.2A, which contains a subset Ta L1Hs), was added were digested with Sau3AI and AccI to release the L1Hs 3′ UTRs. Samples 2 and 3 were mixed in varying ratios to represent 0, 700, 1050, 1400, and 2100 relative copies of L1Hs per haploid genome. Samples (1 μg) of each were Southern blotted and hybridized to oligomer C, a L1Hs-Ta-specific probe. The relative activity of the hybridized bands was measured on a PhosphorImager (Molecular Dynamics). Results indicate a relative copy number of 2250 for the Ca-2 band and a linear relationship of copy number to signal in the standard lanes.