Geometric definition of terms and concepts.

For a given inheritance class Q (e.g., additivity, dominance, epistasis, etc.; see below), the BLUPs for each strain’s male- (q_M) and female-specific (q_F) variance components from models that were fit separately to male and female data sets represent axes of variation that can be plotted in a bivariate relationship (solid lines). These coordinate systems can be rotated 45° (see Materials and methods) to derive the SA (q_SA) and SC (q_SC) dimensions (dashed lines) for each inheritance class. BLUP, best linear unbiased prediction; SA, sexually antagonistic; SC, sexually concordant.