Basalin was ablated in trypanosomes expressing mNG::basalin and PF16::mScarlet-I to determine the effect of basalin ablation upon newly built axonemes. (A–C) Shows non-induced cells. (A) A cell with one nucleus and one kinetoplast (1k1n) shows PF16 incorporation into the axoneme in the early stages of flagellum construction. (B) and C) show cells with 2k1n and 2k2n, respectively. (D–H) Shows cells after 48 hours basalin RNAi induction. (D) A flagellum in the very early stages of construction is missing both basalin and PF16. Older new flagella that are absent for basalin are either D) missing PF16 altogether or have incomplete PF16 assembly into the flagellum, including F) a fragmented or intermittent signal, (G) a proximal signal that does not extend to the flagellum tip, and H) a distal signal that is missing from the proximal portion of the axoneme. (I) Quantification of non-induced vs induced dividing cells at different cell-cycle positions shows that the probability of PF16 being assembled into newly-made axonemes increases with cell-cycle progression (non-induced 1k1n N = 22, 2k1n N = 50, 2k2n N = 45; induced 1k1n N = 38, 2k1n N = 60, 2k2n N = 62).