Predicted ancestral marsupial and therian karyotypes. (A) The 2n = 14 ancestral marsupial karyotype, predicted based on comparative mapping data, are colour-coded to show homology to human chromosomes (same colour-code as shown in Figure 6). Segments from different human chromosomes with known associations in eutherians (light grey) indicated to the left of the chromosomes. Associations of genes in chicken are indicated in dark grey with the number of the chicken chromosome shown above. Dotted lines indicate blocks from the same chicken or ancestral eutherian chromosome. (B) The predicted 2n = 19 therian ancestral karyotype. Chromosomes have been colour-coded to reflect homology with human chromosomes (refer to key in Figure 6).