Table 1. Predicted phenotypic comparisons in offspring from the quantitative complementation test if Pappa2 is or is not the quantitative trait gene (QTG), i.e., the gene responsible for the effect of the QTL.

Mouse heterozygous for constitutive Pappa2 disruption (on C57BL6 background)
		X
Mouse heterozygous for C57BL6 and DBA2 QTL alleles (on DBA2 background)
		↓
	Offspring of four possible genotypes:disrupted or intact C57BL6 Pappa2 allele from one parent, and C57BL6 or DBA2 QTL from other parent
	C57BL6/disrupted		DBA2/disrupted	C57BL6/intact	DBA2/intact
If Pappa2 is responsible for the effect of the QTL, the genotype at the QTG will be:	C57BL6/disrupted		DBA2/disrupted	C57BL6/C57BL6	DBA2/C57BL6
	Prediction: The phenotypic difference between C57BL6/disrupted and DBA2/disrupted will be greater than the phenotypic difference between C57BL6/C57BL6 and DBA2/C57BL6. Little difference is expected between the C57BL6/C57BL6 and DBA2/C57BL6 genotypes because the C57BL6 allele is partially dominant [12].
If Pappa2 is not responsible for the effect of the QTL, The genotype at the QTG will therefore be:	C57BL6/C57BL6		DBA2/C57BL6	C57BL6/C57BL6	DBA2/C57BL6
	All offspring will inherit an intact C57BL6 allele at the QTG, even where they inherit a disrupted Pappa2 allele.Prediction: The phenotypic difference between C57BL6/disrupted-Pappa2 and DBA2/disrupted-Pappa2 will be equal to the phenotypic difference between C57BL6/intact-Pappa2 and DBA2/intact-Pappa2.