Table 1. Sex-specific fitness at a diploid gene with SA alleles¹.

Genotype	AfAf	AfAm	AmAm
Female fitness	W	W(1 − sfhf)	W(1 − sf)
Male fitness	V(1 − sm)	V(1 − smhm)	V
Mean relative fitness2	1 − sm/2	1 − (sfhf + smhm)/2	1 − sf/2

¹W and V scale the relative fitness values of the three genotypes to absolute fitness. Remaining parameters are assumed to fall with the biological range: 0 < s_f, s_m < 1; 0 < h_f, h_m < 1.

²Relative fitness for each sex is scaled against the fitness of the best genotype in that sex (e.g., for females: 1, 1 − s_fh_f, and 1 − s_f for genotypes A_fA_f, A_fA_m, and A_mA_m, respectively). The mean relative fitness of each genotype is the average of the male and female relative fitnesses. Net overdominance occurs when the mean relative fitness of the A_fA_m genotype is higher than the mean relative fitness of both homozygous genotypes.

Abbreviations: A_f, female-beneficial allele; A_m, male-beneficial allele; h_f, dominance coefficient of the A_m allele in females; h_m, dominance coefficient of the A_f allele in males; SA, sexually antagonistic; s_f, the cost to females of being homozygous for the A_m allele; s_m, the cost to males of being homozygous for the A_f allele.