Construction of AT-rich and GC-rich plasmids.

Eight non-coding AT-rich and GC-rich sequences of 1 kb in size were amplified from the genomes of Arabidopsis thaliana and Chlamydomonas reinhardtii, respectively. Sequences were inserted into two different plasmid backbones (pJet and pBAV) to exclude plasmid-specific effects. Different plasmid-insert combinations were treated as independent replicates. All plasmids contained an origin of replication (ori), a resistance cassette (R), and one of the inserts (AT-rich DNA: green label, GC-rich DNA: orange label).