Figure 11: Density of interspersed repeat classes at different (G+C) content in the mouse (a) and human (b) genomes.
From: Initial sequencing and comparative analysis of the mouse genome
In both species, there is a strong increase in SINE density and a decrease in L1 density with increasing (G+C) content, with the latter particularly marked in the mouse. Another notable contrast is that in mouse, overall interspersed repeat density gradually decreases 2.5-fold with increasing (G+C) content, whereas in human the overall repeat density remains quite uniform. This reflects both the abundance of L1 elements in the mouse (G+C)-poor regions and the unusually high density of Alu in human (G+C)-rich regions.
