The proportion of variance accounted for by strain varies between the sexes for many traits. For some traits, females have a higher proportion of non-genetic variation and for others males exhibit more non-genetic variation (Fig. 1b). Across test batteries, except for adrenal weights, the main effect of strain consistently accounts for most of the variation. The partial ω2 for the main effects of sex were considerably lower than the strain main effects, except for left and right adrenal weight measures (Table 3). However, sex × strain interaction effects were of greater magnitude than the main effects of sex, though not as large as strain effects.
