Résumé
Sequence Demarcation Tool (SDT) is a free user-friendly computer program that has been adopted by many geminivirologists as a means of robustly and reproducibly using pairwise genetic identity calculations to classify geminivirus whole genome sequences. As input SDT takes unaligned sequences and it outputs publication quality pairwise identity plots and color-coded distance matrices. Whereas the distance plots are useful for guiding the establishment of strain, species or genus demarcation thresholds that will yield minimal classification conflicts, the distance matrices aid the classification of sequences according to the taxonomic demarcation criteria of the International Committee on Taxonomy of Viruses. Accordingly, over the past 10 years, SDT has been extensively used for the establishment of new genera in the family Geminiviridae and for the classification of hundreds of new species within individual geminivirus genera.