IFT trains are found closer to doublets 4 and 7 compared with doublets 3 and 8. (A) 3D view of a rare flagellum where individual doublets could be discriminated. Segmentation was performed to highlight the vicinity of the IFT trains (red) and microtubule doublets 3 (dark green), 4 (light green), 7 (light blue), and 8 (dark blue). (B) Plots representing the distances between the center of the skeleton for the indicated IFT trains and that of the microtubule doublets along their length using the same color code. In this flagellum, IFT trains are found closer to doublets 4 and 7.