Mutation Load: The Fitness of Individuals in Populations Where Deleterious Alleles Are Abundant

Supplementary Data

• Download all Supplemental Material as a PDF. Includes Supplemental Text 1: The Ecological Effects of Mutation Load, Supplemental Figure 1 (also reproduced below), and Supplemental Figure 2 (also reproduced below)

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  Supplemental Figure 1. The relative population size (i.e., the population size with load divided by the size of an otherwise similar unloaded population) under various types of load and strong interspecific competition. The red lines show results for load on the fecundity rate b, the blue lines show results for load on juvenile resource acquisition rate, and the black lines are for load on adult acquisition rate. When load affects acquisition, it affects the ability of the organism to acquire both its favored and less favored resource. In each case, the life stage that experiences interspecific competition for resources has c = 0.9. The default parameters for these graphs have equal parameters for both species b = 1, d = 0.1, m = 1, a = 1, c = 0 for the intraspecific competition stage, I = 10,000 for the stage with intraspecific competition and I = 1000 for the stage with interspecific competition. Thus the interspecific competition is much more important in determining the equilibrium population size, but equilibrium size depends strongly on load on acquisition rate during interspecific competition. Load on fecundity or on acquisition rate during interspecific competition can have strong effects on equilibrium population size, largely unaffected by the weak intraspecific competition during the other life stage.

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  Supplemental Figure 2. The relative population size (i.e., the population size with load divided by the size of an otherwise similar unloaded population) under various types of load and strong intraspecific competition. The red lines show results for load on the fecundity rate b, the blue lines show results for load on juvenile resource acquisition rate, and the black lines are for load on adult acquisition rate. When load affects acquisition, it affects the ability of the organism to acquire both its favored and less favored resource. In each case, the other life stage experiences interspecific competition for resources with c = 0.9. The default parameters for these graphs have equal parameters for both species b = 1, d = 0.1, m = 1, a = 1, c = 0 for the intraspecific competition stage, I = 1000 for the stage with interspecific competition and I = 100 for the stage with intraspecific competition. Thus the intraspecific competition is much more important in determining the equilibrium population size. In such a case, the acquisition rate is relatively unimportant, much as predicted from the one-stage intraspecific competition models. Load on fecundity affects numbers of juveniles at equilibrium almost proportionately, but fecundity load has weak effects on adult numbers if there is strong intraspecific competition on juveniles.