Fig. 2. Electron microscopy of flight muscle from fln⁰, wild-type and transgenic flies. All pictures are from 2–5-day-old adult IFM. (A,B), fln⁰; (C,D), wild-type; (E,F), P{fln⁺}0.2; (G,H), P{fln⁺}2.2; (I and J), P{fln⁺}0.2. A, C, E, G, I are longitudinal sections; B, D, F, H, and J are cross sections. Note that the highly disrupted sarcomere structure in fln⁰ (in A,B) is no longer evident in the rescued line. However, there are fewer thick filaments per myofibril cross-sectional area. G and H, flies expressing four copies of fln⁺ have normal IFM. I and J, are examples of occasional defects seen in P{fln⁺}0.2 flies. Bar, 0.5 µm.