Extended Data Figure 9: Telencephalic gene expression patterns in lamprey embryos.

a–p, Gene expression patterns in L. japonicum stage-26 and -27 (ref. 33) embryos, stained using probes for Nkx2.1/2.4A (a, b), Nkx2.1/2.4B (c, d), Nkx2.1/2.4C (e, f), Pax6 (g), DlxA (h), HhA (i, j), HhB (k, l), HhC (m, n) and HhD (o, p). Dotted lines indicate the telencephalic border distinguished by the anterior intraencephalic sulcus²⁵. The expression domains of Pax6 (g) and DlxA (h) in the telencephalon pallial and subpallial subdivisions, respectively. Although the previously reported Nkx2.1/2.4A is not expressed in the telencephalon³⁶, Nkx2.1/2.4B and Nkx2.1/2.4C are expressed in the rostral telencephalon (arrowheads), suggesting the presence of the MGE in the lamprey. We did not detect expression of any Hedgehog genes in the rostral telencephalon²⁵ (i–p). q, Summary of the expression patterns of Nkx2.1/2.4 and Hedgehog genes of L. japonicum at embryonic stages 17–30 examined by whole-mount in situ hybridization. en, endostyle; ptu, posterior tuberculum⁴⁷. See Figs 1 and 2 for other abbreviations. Scale bar, 200 μm.