Chapter 25, Problem 8EQ

 All of the homeotic genes in Drosophila have been cloned. As discussed in Chapter 21, cloned genes can be manipulated in vitro. They can be subjected to cutting and pasting, gene mutagenesis, etc. After Drosophila genes have been altered in vitro, they can be inserted into a transposon vector (i.e., a P element vector), which can be injected into Drosophila embryos. The P element then transposes into the chromosomes, thereby introducing one or more copies of the altered gene into the Drosophila genome. This method is termed P element transformation.

With these ideas in mind, how would you create a gain-of-function mutation that caused the Antp gene to be expressed where the abd-A gene is normally expressed? What phenotype would you expect for flies that carried this altered gene?