Independent segregation for the traits of myoclonic jerk threshold in [C57BL/6J × DBA/2J] F1 hybrid mice. The mean latency to the first myoclonic jerk, per flurothyl trial throughout the repeated flurothyl model, for C57BL/6J (black circles), DBA/2J (red squares), and [C57BL/6J × DBA/2J] F1 hybrid (blue open squares) mice (data from C57BL/6J and DBA/2J mice have been replotted from Figure 1 for this comparison). Specific comparisons between C57BL/6J and DBA/2J mice on the myoclonic jerk threshold, demonstrated a significant group by trial interaction (F7,336 = 12.7, P < 0.0001), and significant differences between groups (F1,48 = 8.0, P < 0.007) and between trials (F7,336 = 8.6, P < 0.0001). * denotes significantly different from C57BL/6J (P < 0.04); # denotes significantly different from DBA/2J (P < 0.03); $ denotes significantly different from C57BL/6J (P < 0.03).