Editing Quantitative genetics (section)

====Full-sibs (FS)====
As explained in the introduction, a method similar to that used for mid-parent/progeny covariance is used. Therefore, an ''unadjusted sum of cross-products'' (USCP) using all products—{''' parent-pair-frequency * the square of the offspring-genotype-mean '''}—is adjusted by subtracting the '''{overall genotypic mean}<sup>2</sup> ''' as ''correction factor (CF)''. In this case, multiplying out all combinations, carefully gathering terms, simplifying, factoring, and cancelling-out is very protracted. It eventually becomes:

'''cov(FS) = pq a<sup>2</sup> + p<sup>2</sup> q<sup>2</sup> d<sup>2</sup> = {{sfrac|1|2}} s<sup>2</sup><sub>A</sub>  + {{sfrac|1|4}} s<sup>2</sup><sub>D</sub> ''', with no dominance having been overlooked.<ref name="Crow & Kimura"/> {{rp|132–141}}<ref name="Falconer 1996"/> {{rp|134–147}}