Figure 3

Conserved synteny between 2R-generated chromosome blocks. The identified paralogous chromosomal regions in the human, chicken and spotted gar genomes. In addition to the main gene families, the neighboring gene families with a full quartet of paralogous genes (ATP2B1, CAMK1, L1CAM and PLXNA) are included for reference. Colors are applied following the human and chicken chromosomes in order to show conserved synteny as well as sequence homology between species. Four paralogous regions can be observed in the human and spotted gar genomes. In the chicken genome the orthologs of the human genes on chromosome X could not be identified in the genome assembly. Orthologs for the genes on human chromosomes 7 and 12 are located on chromosome 1 in chicken and LG8 in spotted gar, indicating a split of this region in the human lineage. Several chicken genes have not been mapped to any chromosomal location. Their sequences for phylogenetic analyses were retrieved from NCBI. To facilitate comparisons between species, the names of the human orthologs have been applied to the chicken genes except for the visual opsin and OT/VP-R families where the gene names used in Figures 1 and 2 are applied. Note that the human and chicken V2 receptor sequences correspond to different subtypes: V2A and V2C respectively (Figure 2).