A scheme to illustrate the number of genes derived from the ancestral gene set of the camera eye in each species lineage. This topology has been accepted by many molecular biologists and developmental biologists (Schmidt-Rhaesa 1998; Adoutte et al. 2000; Girbet et al. 2000; Morris 2000; Peterson et al. 2000, 2001). The number of conserved genes is shown below each species name. The numbers in italic represent the number of gene loss in each branch. (*) The number of the ancestral gene set that was obtained from the estimation of homologous genes between octopus-eye ESTs and the genomes of deuterostomes and out-group bilaterian species. (**) The number of conserved genes shared among the ancestral gene set and the genomes of the mosquito and fly as the representatives of conserved genes in insects. (***) The union of conserved genes in Fugu, mice, and humans as representatives of conserved genes in vertebrates.
