Figure 2

Uncovering genome duplications through comparative analysis with related sequences. The hypothetical genomes of two related organisms are shown, each containing the same set of genes. Both genomes are initially identical, but the genome of Organism 1 is duplicated, resulting in a second identical set of chromosomes and genes. After some time, homologous chromosomes lose a different set of genes, keeping two copies for only a minority of the duplicated genes. For the sake of simplicity, the genome of Organism 2 is assumed to remain unchanged. Within Organism 1, the only evidence for a duplication event comes from the conserved order of the anchor points formed by genes 1 and 11 (indicated by boxed regions). Comparison with the genome of Organism 2, however, shows a pattern of so-called 'double conserved synteny' where the duplicated nature of Organism 1 is revealed.