Homologous RGA clusters in the five plant genomes analyzed. Genomic segments and the genes are drawn according to their relative sizes. Squares above the lines represent genes located on the Crick strand and those below the lines represent genes on the Watson strand. The red line indicates the reciprocal best hit. Colored squares represent the genes containing R gene specific domains and the gray squares represent the intervening genes. The green squares represent genes with both NBS and LRR domains, the blue ones represents those with LRR, the yellow ones represents those with NBS, and the red ones represents those with fragmented NBS. All the genomic segments are drawn from 5' to 3'. The diagram is drawn using GenomePixelizer .