Figure 3.—

Fly cross schemes for genetic deficiency screen. (A) In cross scheme 1, progeny flies bearing CAG repeats were selected by fluorescence by the screening for flies expressing DsRed from the CAG repeat transgene in thoracic muscle with the Act88F–GAL4 driver. About 50 crosses were performed in this manner. (B) In cross scheme 2, a balancer on the third chromosome was introduced into the deficiency lines, to allow selection of progeny of cross C by selecting against the TM6b, Tb balancer. About 70 crosses were performed in this manner.