Table 2.

Relative fitnesses of diploid genotypes for the two‐locus underdominance system

	A w B w	A w B t	A t B w	A t B t
A w B w	1	0	0	${\left(1-s_p\right)}^{1/2}$
A w B t	0	0	${\left(1-s_p\right)}^{1/2}$	${\left(1-s_p\right)}^{1/2}$
A t B w	0	${\left(1-s_p\right)}^{1/2}$	0	$\left(1-s_p\right)$
A t B t	${\left(1-s_p\right)}^{1/2}$	${\left(1-s_p\right)}^{1/2}$	$\left(1-s_p\right)$	$\left(1-s_p\right)$

Columns and rows show haplotypes inherited from each parent. Fitness is shown with multiplicative cost (s _p) of the payload allele.