Percent AT (•) and GC (•) content at the last 15 bp of sheared inserts. Sheared genomic DNA was cloned into a plasmid vector and sequenced by Dye Primer chemistry on ABI 373 or 377 instruments. The first 15 bases of 544 insert sequences were imported into StatView 4.5 (Abacus, Berkeley, CA). The percent AT and GC content was determined for each position from the end of the insert and compared to the overall AT and GC content, and the results were displayed graphically.