Editing Quantitative genetics (section)

==== Genotype substitution – expectations and deviations====
The zygote genotypes are the target of all this preparation. The homozygous genotype '''AA''' is a union of two ''substitution effects of A'', one from each sex. Its ''substitution expectation'' is therefore '''β<sub>AA</sub> = 2β<sub>A</sub> = 2''q''β''' (see previous sections). Similarly, the ''substitution expectation'' of '''Aa''' is '''β<sub>Aa</sub> = β<sub>A</sub> + β<sub>a</sub> = (''q''-''p'')β'''; and for '''aa''', '''β<sub>aa</sub> = 2β<sub>a</sub> = -2''p''β'''. These ''substitution expectations'' of the genotypes are also called ''breeding values''.<ref name="Falconer 1996"/>{{rp|114–116}}

''Substitution deviations'' are the differences between these ''expectations'' and the ''gene effects'' after their two-stage redefinition in the previous section. Therefore, '''d<sub>AA</sub> = a•• - β<sub>AA</sub> = -2''q''<sup>2</sup>d''' after simplification. Similarly, '''d<sub>Aa</sub> = d•• - β<sub>Aa</sub> = 2''pq''d''' after simplification. Finally, '''d<sub>aa</sub> = (-a)•• - β<sub>aa</sub> = -2''p''<sup>2</sup>d''' after simplification.<ref name="Falconer 1996"/>{{rp|116–119}} Notice that all of these ''substitution deviations'' ultimately are functions of the gene-effect ''d''—which accounts for the use of ["d" plus subscript] as their symbols. However, it is a serious ''non sequitur'' in logic to regard them as accounting for the dominance (heterozygosis) in the entire gene model : they are simply ''functions'' of "d" and not an ''audit'' of the "d" in the system. They ''are'' as derived: ''deviations from the substitution expectations''!

The "substitution expectations" ultimately give rise to the '''σ<sup>2</sup><sub>A</sub>''' (the so-called "Additive" genetic variance); and the "substitution deviations" give rise to the '''σ<sup>2</sup><sub>D</sub>''' (the so-called "Dominance" genetic variance). Be aware, however, that the average substitution effect (β) also contains "d" [see previous sections], indicating that dominance is also embedded within the "Additive" variance [see following sections on the Genotypic Variance for their derivations]. Remember also [see previous paragraph] that the "substitution deviations" do not account for the dominance in the system (being nothing more than deviations from the ''substitution expectations''), but which happen to consist algebraically of functions of "d". More appropriate names for these respective variances might be '''σ<sup>2</sup><sub>B</sub>''' (the  "Breeding expectations" variance) and '''σ<sup>2</sup><sub>δ</sub>''' (the "Breeding deviations" variance). However, as noted previously, "Genic" (σ <sup>2</sup><sub>A</sub>) and "Quasi-Dominance" (σ <sup>2</sup><sub>D</sub>), respectively, will be preferred herein.