High‐resolution mapping of the Gli3 deletion in the mouse extra‐toes H mutant

Extra‐toes is a semidominant mutation that affects the Gli3 gene and provokes limb and brain abnormalities. Among the different alleles of this mutation, Xt H is due to a deletion that has not yet been fully characterized. Using a PCR‐based strategy, we undertook a high‐resolution mapping of this deletion and confirmed that Xt H is a null allele of Gli3 . We further designed a PCR test to identify unequivocally heterozygous and homozygous embryos from their wild‐type littermates. Despite the length of the Xt H deletion, available data on the mouse genome indicate that no genes other than Gli3 are deleted in Xt H mutants. Thus, the Xt H mutation can be used as a model for studying the effects that absence of Gli3 function has during development. genesis 45:107–112, 2007. © 2007 Wiley‐Liss, Inc.