Figure 8.

The evolution of gene orders along orthologous chromosomes. (A) Xma1 vs. medaka chromosome Ola7 shows mostly conserved gene orders with a few short inversions. (B) Xma1 gene order plot vs. green pufferfish Tni9 shows a few more irregularities and that the initial 4 Mb on Xma1 do not have any orthologs along Tni9, because these sequences that should be on Tni9 were not assembled into the chromosome. (C) Threespine stickleback chromosome Gac12 shows a few more rearrangements with respect to Xma1. (D) Although zebrafish chromosome Dre23 is reciprocally fully orthologous to Xma1, the order of genes along the chromosome is quite different. (E) The human orthologs of Xma1 genes lie mainly on four human chromosomes, Hsa1, -3, -12, and -20. (F–I) Gene order plots for human chromosomes Hsa1, -3, -12, and -20, respectively, resemble those for zebrafish. Inversions between medaka and platyfish are colored differently to compare fates in different species.