Fig. 2. Pairwise dot plots and chromosome-chromosome significance.

(Top) Dot plots showing the ordinal location of orthologous genes between jellyfish and amphioxus (left) and sponge (right). Genes with orthologs are numbered consecutively without regard to distance. (Bottom) Sponge versus amphioxus dot plot (left) and chromosome-chromosome significance by Fisher’s exact test (right). In dot plots, colored dots represent genes with consistent statistically significant conserved chromosomal synteny as shown in Figs. 1 and 3; genes of variable synteny are shown in gray. n.s., not significant.