Selection on BEC at the end of the 4 hours drinking session on Day 2 of the DID test resulted in a 3.6-fold increase in the average BEC across 11 generations. Figure 1A shows the average BEC for each generation. BEC in the foundation population of HS/Npt mice (S0) averaged .30 mg/mL. Inverted open triangles indicate the average BEC of individuals selected as parents for each subsequent generation. For example, by S4, BEC in HDID-1 mice averaged .43 mg/mL. From this population, BEC in the 13 mating pairs that were chosen to produce the S5 generation averaged .83 mg/mL. Their S5 offspring had average BECs of .61 mg/mL. By S11, the average BEC was 1.07 mg/mL for the offspring population, an increase over the foundation population of 262%.
