Breaking strategy of large clusters. A breaking strategy was used to reduce the size of large clusters. Each sequence in a cluster was BLASTed against the others and e-values were used to build an adjacency matrix (see Materials and Methods). For example, an e-100 value will result in a distance of 1 cm between two sequences. Only values below e-25 were used for graphical display. GRAPH9 was used to flag bridges (articulation points where an EST links two potential sub-clusters) and manually split a cluster into distinct sub-clusters. A) Example of a cluster region where specific ESTs (in red) can be manually transferred to sub-clusters (based on the smallest e-value). B) Example of a cluster region that could not be broken into sub-clusters due to the complex interrelations between ESTs.