Fig. 3. Transgene coplacement. Two inserts (1 and 2, red), each containing a cloned fragment, such as a genomic rescue fragment, are integrated into a P element that contains appropriately positioned loxP (yellow) and FRT (pink) sites. Cre recombination results in the removal of insert 2, whereas FLP recombination results in the removal of insert 1, positioning either insert in the same orientation at the same locus (indicated in blue), thereby neutralizing position effects. In each case, recombination events are identified by the loss of a dominant marker (green).