Germ line, cre mediated recombination between Hoxd12tm2Ddu and Hoxd13tm2Ddu maintained in cis results in the deletion of the 3' end of exon 1 Hoxd12tm2Ddu through the lacZ insertion in exon 1 Hoxd12tm2Ddu. The lacZ cassette inserted into Hoxd13 is retained. In situ hybrizidation confirmed expression of the fusion transcript in a similar pattern observed for Hoxd11. (J:47366)