Clusters of R-genes in the MELO04258-MELO3C004324 region, phylogeny relationships, and synteny with cucumber and watermelon. Melon genes, represented by vertical lines accompanied by gene Ids, are grouped in four sub-clusters based on proximity: TIR-NBS-LRR genes in clusters A (red lines), B (yellow lines), and C (green lines); CC-NBS-LRR genes in cluster D (blue lines). Syntenic genes in cucumber and watermelon are in the same colour as their melon orthologues. Colored lines connect pairs of genes in two different species showing the highest protein identity/blastp e-values; however, when the genes in a cluster are so similar as to unequivocally establish one-to-one orthology relationships, a colored line connects a gene to a cluster of genes instead. ORFs with homology to NBS-LRR R-genes but too short as to be considered true genes are in grey. Gene Ids in red indicate putatively expressed genes (on the basis of information from EST databases). Direction of transcription of all genes is left to right, but for the few genes marked with red arrows. For each species, phylogeny relationships based on the alignment of the conserved NBS regions are also shown. Note that branch lengths have no phylogeny meaning due to the original trees having been distorted to project them on the actual disposition of genes on the genome.