TABLE 1.

Expectation (ɛ(X)), variance ((X)), and conditional expectation (ɛ(X | QTL i)) of the contrast between the two homozygous marker classes at the position of QTL i and conditional expectation (ɛ(X | QTL i × QTL j)) of the interaction between the two homozygous marker classes at the positions i and j for X = Z₁, Z₂, Z₃, and H₃ in terms of genetic effects of the F₂-metric under digenic epistasis in the absence of linkage

	Statistica
Variable X	ɛ(X)		ɛ(X | QTL i)	ɛ(X | QTL i × QTL j)
Z1				aaij + ddij
Z2				adij + daij
Z3				2ddij
H3	μ		ai	aaij

For description of Z₁, Z₂, Z₃, and H₃ and for notation of genetic effects see materials and methods.

^aSummation is over the entire set of QTL involved in the trait expression.