Mice homozygous for the Wnt9bc allele are viable and fertile, with loxP sites flanking exon 2 of the targeted gene. When bred to mice that express Cre recombinase, the resulting offspring will have this region deleted in the cre-expressing tissue(s). Such deletion is predicted to result in out-of-frame splicing of exon 1 to exon 3, and consequently a mutant transcript that would encode a nonfunctional peptide comprising the first 27 amino acids of Wnt9b that includes the signal peptide. These Wnt9bc mice may be useful in generating conditional mutations for studying the role of Wnt9b (and other Wnt family members) in development and canonical Wnt signaling cascades, including metanephric kidney and urogenital system development. The Jackson Laboratory 2024, used with permission.