Fig. 8. Gli2 knock-in mice expressing Gli1 develop hair defects. (A) Gli2^1ki/+ mice develop hair defects at three months of age. (B) Gli2^n1ki/+ mice are normal, whereas Gli2^n1ki/n1ki mice develop hair defects and are much smaller than Gli2^n1ki/+ littermates. Shown at 3 months of age, the Gli2^n1ki/n1ki mouse weighed 15 g and the Gli2^n1ki/+ mouse weighed 29 g. (C) Removal of one copy of Gli3 enhances the hair loss defect in Gli2^1ki/+;Gli3^+/– mice at 6 weeks of age. (D) Expression of one copy of Gli1 from the Gli2 allele enhances the polydactyly in Gli2^1ki/+;Gli3^+/– mice.