Fig. 7. Expression boundaries of regulatory genes in the diencephalon and telencephalon. (A-D) Diencephalic expression domains for LjPax6 (A), LjTTF1 (B), LjDlx1/6 (C) and LjOtxA (D). The outline of the diencephalon is shown by white lines. For each figure, the contours of the gene expression domain are shown by a blue line, which is identified anatomically by the relative positions of the telencephalon (arrowheads), the rostral end of the notochord (white arrows), and the anterior end of the epiphysis (black arrows). Red hatched lines indicate the domains where LjPax6 and LjDlx1/6 are both expressed. White arrowheads in C indicate the expression in the tissue lateral to the brain. (E-G) Regionalized expression patterns of regulatory genes in the stage 26 lamprey telencephalon showing the possible tripartite configuration. In all three embryos, broken white lines indicate the anterior intraencephalic sulcus and arrows indicate the hypothetical boundary between the dorsal and ventral telencephalon assumed in the present study. Expression patterns of LjPax6, LjDlx1/6 and LjEmx are shown in E-G, respectively. (E) LjPax6 is expressed in the dorsal part of the telencephalon (DP+VP). (F) LjDlx1/6 is expressed in the ventral telencephalon. (G) Weak expression of LjEmx is restricted to the dorsal region of the telencephalon, possibly corresponding to the dorsal pallium. Abbreviations: DI, diencephalon; DT, dorsal telencephalon; EP, epiphysis; VT, ventral telencephalon.