Withdrawal Seizure-Resistant, replicate 1 (WSR1) mice were selectively bred for low alcohol withdrawal convulsion severity after 72hr of continuous chronic ethanol vapor inhalation. The founder stock for selective breeding was the HS/Ibg heterogeneous stock that was developed by Gerald McClearn and colleagues (The Institute for Behavioral Genetics, Boulder, Colorado) as an 8-way cross of the following inbred strains obtained from the Cancer Research Genetics Laboratory at UC-Berkeley: A, AKR, BALB/c, C3H/2, C57BL, DBA/2, Is/Bi, and RIII.
Eighteen matings of Generation 30 HS/Ibg mice were randomly divided into 2 groups of 9 families each. These generation 31 mice became the foundation (So) population for selection based on alcohol withdrawal severity. One group of 9 familes was designated Replicate 1, the other Replicate 2. To establish the Withdrawal Seizure-Resistant Replicate 1 (WSR1) line the lowest scoring male and female from each family were selected. Selected progeny from each family were then mated using a rotational system – female from Family 1 mated to male from Family 2, female from Family 2 mated to male from Family 3, etc. Two to six reserve families were generated to provide back up. The selection process was repeated for 26 generations. Relaxed breeding (random selection of breeders from within each family) has continued for approximately 100 generations. The MMRRC imported a acombination of the 9 families to form the WSR1 line in 2016.
