Evidence of Selection upon Genomic GC-Content in Bacteria
The figure shows the effect of selection in favour of GC on Z. The relationship between Zpred and S (2Nes) for three values of f, the equilibrium GC-content when there is no selection (i.e. the mutation bias); from top to bottom f is 0.7, 0.5 and 0.3. In these examples 2Neμ = 0.1 and n = 10; qualitatively similar patterns are observed for other values of these two parameters.