. 2009 Mar 12;364(1520):1107–1115. doi: 10.1098/rstb.2008.0238

Table 3.

An example of a system where imprinting of a locus in offspring is controlled by the maternal genotype. (The locus expressed in offspring has two alleles, A₁ and A₂, with frequencies p₁ and p₂ while the maternal genotype is defined by a second locus that has two alleles, B₁ and B₂, with frequencies x₁ and x₂. The cells show the expected phenotypes and frequencies (in parentheses) of offspring for each of the 12 maternal–offspring genotype combinations (where offspring genotypes are given as paternally inherited allele followed by maternally inherited allele). The locus shows imprinting with maternal expression in offspring of the B₁B₁ mothers, but biallelic expression with an additive effect in the offspring of other mothers. The A₁ allele has a+a effect on the offspring phenotype while the A₂ allele has a −a effect. The column labelled ${\bar{z}}_{maternal}$ gives the mean phenotypes of offspring produced by the three maternal genotypes at the B locus while ${\bar{z}}_{offspring}$ gives the mean phenotypes of offspring with each of the four ordered genotypes at the A locus.)

		offspring genotype

		A₁A₁	A₂A₁	A₁A₂	A₂A₂	${\bar{z}}_{maternal}$
maternal genotype	B₁B₁	+a ( $p_{1}^{2} x_{1}^{2}$ )	+a ( $p_{1} p_{2} x_{1}^{2}$ )	−a ( $p_{1} p_{2} x_{1}^{2}$ )	−a ( $p_{2}^{2} x_{1}^{2}$ )	+a (p₁−p₂)
	B₁B₂	+a ( $p_{1}^{2} 2 x_{1} x_{2}$ )	0 ( $p_{1} p_{2} 2 x_{1} x_{2}$ )	0 ( $p_{1} p_{2} 2 x_{1} x_{2}$ )	−a ( $p_{2}^{2} 2 x_{1} x_{2}$ )	+a (p₁−p₂)
	B₂B₂	+a ( $p_{1}^{2} x_{2}^{2}$ )	0 ( $p_{1} p_{2} x_{2}^{2}$ )	0 ( $p_{1} p_{2} x_{2}^{2}$ )	−a ( $p_{2}^{2} x_{2}^{2}$ )	+a (p₁−p₂)
${\bar{z}}_{offspring}$		+a	+a $x_{1}^{2}$	−a $x_{1}^{2}$	−a