Figure 1

Distribution of isochores according to GC levels. The histograms show the distribution (by weight; see Text) of isochores as pooled in bins of 0.5% GC from chimpanzee, dog, mouse, opossum and platypus. Total amounts of sequences are calculated from the sums of isochores; colors represent the five isochore families. Values at minima were split between the two neighbouring families (histogram bars with mixed colors). A comparable plot for the human genome [3] is reported for the sake of comparison.