Figure 1

The identification algorithm. The flow chart diagrams the Blast-based approach used to identify helitron sequences initially. Approximately 40 bp were isolated from 5' and 3' ends of known helitrons, along with ~40 bp of flanking sequence. These ends were used as blast queries to Plant Genbank; hits to both ends that were <20,000 bp apart (represented by light blue-grey boxes with attaching arrows) were considered putative helitrons. These putative helitrons were screened for redundant or overlapping entries (pink box) to yield predicted helitrons. See Methods for details.