A. Upper panel, schematic of knockout first allele. Colored arrows mark the locations of the primers used for genotyping: black triangle, Neo primers; blue triangle, common loxP primers; orange triangle, WT 80bp primers. Middle panel, summary of live births achieved from mating two NACKKOF/+ mice. Bottom panel, genotyping results from wt and heterozygous pups. B. Top panel, schematic of floxed allele resulting from FLPe recombination. Middle panel, summary of live births achieved from mating two NACKflox/+ mice. Bottom panel, representative genotyping results from wt, heterozygous, and homozygous pups.