Regions of human chromosomes homologous to frog, chicken and opossum chromosomes. Opossum chromosomes 4 (orange) and 7 (purple) both show regions of homology on single human chromosomes 2,3, and 13, supporting their origin from a single ancestral chromosome. Amphibian (blue) and bird (grey). Figure summarizes data from Additional file 3. cen – centromere.
Mácha et al. BMC Genomics 2012 13:315 doi:10.1186/1471-2164-13-315