Duplication of the Adgf-A2, Adgf-A and Adgf-B genes in which both copies of Adgf-A are mutated. The actual combination of open reading frames is: wild-type Adgf-A2, mutant Adgf-A, mutant Adgf-B, w+mW.hs marker (inserted during generation of the duplication), mutant Adgf-A2, mutant Adgf-A, wild-type Adgf-B.