Another study indicated that selection for ethanol drinking had no effect on impulsive choice in mice. Although procedurally that study was very similar to the present experiment, that study used a murine population quite different from the present sets of selected lines (Wilhelm et al., 2007). Specifically, they used the fourth generation of their selected mice (STDRHi2 and STDRLo2) for DD testing. They observed an effect of selection for alcohol drinking (high drinkers: 10.5 ± 0.67 g/kg/d), but compared with the current generations of HAP mice (Line 1: 20.8 ± 0.55 g/kg/d and Line 2: 17.2 ± 0.62 g/kg/d) intake of the high drinking parental line was relatively low. Another possibility is that both their response to selection and their ability to detect genetic correlations may be limited by low genetic diversity compared to the HS/Ibg, as the progenitor population in the Wilhelm et al. study was an F2 derived from 2 inbred strains (C57Bl/6J and DBA2/J), compared to the 8 inbred strain cross that was used to derive the HS/Ibg. Overall, any genetic correlation (or lack thereof) is specific
