TABLE 2.

Model variables and parameters

Terms	Model	Definitions
		Frequency of allele A at trait locus A or allele M at modifier locus M; .
r		Rate of recombination between loci A and M.
		Strength of natural selection acting on genotype i.
		Array of genotype frequencies; .
		Total fitness of genotype i, accounting for both natural and sexual selection. Wi also depends on the composition of the population.
		Total fitness advantage of homozygotes over heterozygotes , accounting for natural and sexual selection.
	(G)	The probability that genotype i joins group j (Figure 1).
	(G)	Strength of assortative mating for a female of genotype j (MM, Mm, or mm); specifically, the probability that a female chooses a mate from within her group. measures the difference in strength of assortment if a female carries allele M instead of m.
	(P)	Strength of assortative mating for a female of genotype j (MM, Mm, or mm) as described by matrix (3).
K = ρ1,j/ρ2,j	(P)	Strength of assortative mating against males that differ by one trait allele relative to those that differby two in the preference-based model.
Ti	(P)	The probability that a female of genotype i accepts a male during a mating encounter, given the current population composition and her preferences.
		A fixed cost that directly selects against assortative mating in proportion to the strength of assortative mating.
		A relative cost that directly selects against assortative mating in proportion to the difficulty of finding a preferred mate.
R	(G)	The rarity of males experienced by females averaged over all groups; ΔR measures the difference in rarity if a female carries allele M instead of m.
θ	(G)	The effect of mating within a group on homozygosity at locus A; Δθ measures the difference in production of homozygotes if a female carries allele M instead of m.
mate1, mate2	(P)	The probability that a potential mate differs by one or two alleles at the A locus.
DAM, DA,M		Linkage disequilibrium within (cis) or between (trans) homologous chromosomes.
DA,A		Excess homozygosity at locus A; measures the effect of the modifier on DA,A following a single round of mating.
DAM,A		Trigenic disequilibrium measuring the association between allele M and excess homozygosity at locus A.

Terms specific to the group-based or preference-based model are denoted in the second column by (G) or (P). The value of a parameter x averaged over the population is denoted by . The QLE value of a variable D is denoted by .