Fig. 5: Conditions of maintenance of polymorphism through antagonistic pleiotropy.
From: Balancing selection via life-history trade-offs maintains an inversion polymorphism in a seaweed fly
a Inversion frequencies at equilibrium and mechanisms of balancing selection emerging from the antagonistic pleiotropy, within the range of parameters explored for the Coelopa frigida wild populations. Female reproductive parameter values were based on experimental values, variability in the duration of the habitat (Avar) was set to 2 days and relative survival rates correspond to low-density conditions. b Male relative survival according to the duration of habitat availability (Amean). Values are normalized relatively to a value of 1 for ββ males. Colours stands for the different inversion genotypes (αα, grey, αβ purple, ββ, yellow). Boxplots show the distribution of 30 replicated simulations, with boxes indicating quartile, central line indicating median and whisker expanding to 1.5 times the interquartile. c Variability in the duration of habitat availability (Avar) further increases the portion of the parameter space leading to polymorphism persistence. The parameter space if defined by Tββ-m = [0.1–1.0] and Amean = [7–20 days], as in panel a. Boxplots show the distribution of 100 replicated simulations, with boxes indicating quartile, central line indicating median, whisker expanding to 1.5 times the interquartile and dots being outliers. d Outcome of simulations within a theoretical parameter space, without differences of parameters between sex nor any environmental effect. Overdominance in total fitness emerges as a result of antagonistic pleiotropy, even in the case of co-dominance for each fitness component (top right corner: Hs = 0.5, Ht = 0.5). Simulations in which dominance for survival (Hs) and reproduction (Ht) are independent show how a reversal of dominance and/or variation in the strength of dominance between components of fitness further expand the range of parameters leading to overdominance and the maintenance of polymorphism. e Outcome of simulations within a theoretical parameter space in which fitness parameters are independent between males and females (Sαα-f is the relative survival of αα females, Sαα-m is the relative survival of αα males, Tββ-f is the relative reproductive success of ββ females, Tββ-m is the relative reproductive success of ββ males), without dominance (Hs = Ht = 0.5) or without any environmental effect. Source data are provided as a Source Data file.
