Fig. 2.

scRNA-seq gene expression states map to the tailbud.

(A) (i) A schematic showing the developmental trajectory of the paraxial mesoderm in the tailbud. All panels show the expression of sox2 (yellow), brachyury (cyan), tbx16 (magenta), and tbx6 (green). (ii) Fluorescent in situ hybridization maps the transcriptional states (numbered) defined by scRNA-seq onto the tailbud. In the dorsal view, the orange lines mark locations of the midsagittal (short line) and parasagittal (long line) slices. (B) Expression of tbx16 (magenta) and tbx6 (green). Vertical lines mark the transition from PZ to PSM and PSM to anterior PSM. Scale bars, 50 μm. (C) Plot of signal intensity in a representative wild-type embryo along the anterior-posterior axis. Vertical bars are cutoffs for the PZ and PSM of 20 and 85% of maximum tbx6 expression, respectively. (D) PZ length normalized to total length of PZ and PSM in wild-type, BMP-inhibited, and FGF-inhibited embryos. (E) PZ area normalized to total area in wild-type and Wnt–inhibited embryos. ***P < 0.001. n.s., not significant. See also fig. S3.