Fig. 2: Single-cell repertoire in the chaetognath P. gotoi.

a, Uniform manifold approximation and projection (UMAP) dimensionality reduction of cell expression profiles from pooled juvenile and adult libraries (Extended Data Fig. 5) with inferred clusters coloured and labelled. b, Dot plot of selected cell-type marker genes for each cluster, with genes selected as markers for in situ hybridization highlighted in blue, and dotted lines separating markers characteristics of broad cell-type categories. c, Summary of SAMap comparisons between chaetognath and selected bilaterians. Dot plot and text labels indicate the number of conserved cell-type genes between P. gotoi and selected species (full species name in Fig. 1b). d, Microphotographs of whole-mount in situ hybridization staining for selected markers in juvenile stages (3 days post-fertilization (dpf)). All in situ hybridization experiments were carried out on at least three distinct individuals. The second row shows higher magnification of images in the first row. Numbers indicate clusters in a that are represented by the labelled cells. Chs2-5 is indicative of the chaete cells located near the grasping spines. Vwf-2 is expressed in the epidermal cells, in a subset of which Wnt1 seems to be localized. Tbx2 and Fmar-5 are expressed in ciliary organs. Cac1a-2 is expressed in the main ventral neural ganglion as well as other cephalic cells. Pxdn-9 marks the papillae sensory cells in the head. A full list of cell-type markers is provided in Supplementary Table 6 and molecular probes are listed in Supplementary Table 7. Scale bars, 50 µm.