Fig. 1

The increasing mean fitness for both random and inbreeding populations with directional selection. Solid-line: the mean fitness curve of the inbreeding population. Dash-line: the mean fitness curve of the random population. Parameters are selection coefficient s=0.2 and the degree of dominant h=0.2 (that is, the genotype are (1,0.96,0.8) and inbreeding coefficient f=0.25 and initial frequency x=0.6