MultiColor FlpOut (MCFO):

In Extended Data Fig. 5, MCFO was used to identify the morphological types of R neurons labeled by R20A02-Gal4. MCFO immunostaining was performed essentially as described in ref. ⁴³. Primary incubation solution contained mouse anti-Bruchpilot antibody (1:30, Developmental Studies Hybridoma Bank, nc82), rat anti-FLAG (1:200, Novus Biologicals), rabbit anti-HA (1:300, Cell Signaling Technologies), and 5% normal goat serum (NGS) in PBST. Secondary incubation solution contained Alexa Fluor 488-conjugated goat anti-rabbit (1:250, Invitrogen), ATTO 647-conjugated goat anti-rat (1:400, Rockland), and Alexa Fluor 405-conjugated goat anti-mouse (1:500, Invitrogen) and 5% NGS in PBST. Tertiary incubation solution contained DyLight 550-conjugated mouse anti-V5 (1:500, Bio-Rad) and 5% normal mouse serum in PBST.