Figure 2: Distribution of the G + C content.

a, Distribution in 5-kb non-overlapping windows across Tetraodon (red squares) and Takifugu (blue circles) scaffolds, and in 50-kb windows in human (black triangles) and mouse (green inverted triangles) chromosomes. Windows containing more than 25% ambiguous or unknown nucleotides (gaps) were excluded from the analysis. b, Cumulative sum of annotated coding bases in Tetraodon and Takifugu (5-kb non-overlapping windows) and human and mouse (50-kb windows) as a function of G + C content. c, In sharp contrast to Takifugu4 the density of genes increases with the G + C content (%) in Tetraodon (red circles) much more than in human (black triangles). d, The three major families of repeats in Tetraodon are not distributed uniformly in the genome: long terminal repeat (LTR) and LINE elements (red diamonds and green squares, respectively) concentrate in (G + C)-rich regions and SINE elements (blue circles) concentrate in (A + T)-rich regions. In contrast, the distribution of these elements is much more uniform in Takifugu (Supplementary Fig. S4).