Figure 1. Tracing individual NB lineages identifies postembryonic progeny of NBs.
(A) Schematic illustration of the strategies used in this study to trace NB lineages. Since expression of GAL4 lines is usually not maintained throughout the development, GAL4 expression was immortalized in progeny of the NBs to identify their postembryonic progeny. The “reporter immortalization” technique requires several steps of transcriptions and recombinations (Awasaki et al., 2014). Thus, cells that are born from initial divisions (marked by asterisk) after the GAL4 presence are not labeled with this technique. (B) Schematic representations of embryonic NBs (left) and their corresponding postembryonic lineages (right) for the T2 segment shown. 30 bilaterally symmetric NBs and 1 medial NBs generate 26 postembryonic lineages. For segment specific differences, see Figure 1—figure supplement 1. Row identity of NBs shown in a color code. Three thoracic specific NB lineages are outlined with a thick line. Thick crosses depict NBs, which are eliminated by apoptosis; thin crosses depict NBs, which are present at early stage embryos, but not detected at stage 17 embryos. Dashed line indicates the midline.
Figure 1—figure supplement 1. Schematic representations of postembryonic lineages in different segments of the nerve cord shown.
