ANOVA revealed a significant line × generation interaction (F4,861=43, p<9 × 10−25). At S5, the difference between the High and Low lines was (in relative units) 3.4±0.2 vs 0.6±0.01 (p<1.2 × 10−5). During selection, there was a significant generation effect for the average baseline withdrawal score (F4,861=40, p<1 × 10−30; Fig. 2c); the average baseline score (relative units) decreased from 1.0± 0.06 to 0.22±0.05 (p<6 × 10−5). At S5, there was no significant difference in baseline withdrawal score between the High and Low lines (0.28±0.06 vs 0.17±0.07).
