Figure 3.

The parameter space (area below dashed lines) supporting the invasion of additive mutations that helps granddaughters (with benefit B_Helped) at the expense of their grandsons (with cost C_Harmed). X_GP depicts mutations on the X that affect all grandparents; X_GM depicts mutations on the X that affect only grandmothers; X_PGM depicts mutations on the X that affect only patrilineal grandmothers; A_{GP, GM or PGM} depicts mutations on the autosomes and affects all grandparents, only grandmothers or only patrilineal grandmothers, respectively.