Figure 3
Expression of Hox1 in developmental stages of Octopus vulgaris. Dorsal (D)–ventral (V), anterior (A)–posterior (P), and left (L)–right (R) axes indicate the orientation. Lateral views (A,F). Anterior view (B,C) and (D,E) (posterior view). Stage XIV (A–C), stage XVIII (D–F). (A) In stage XIV individuals, Hox1 transcripts are present in the lateral lips (ll), the ventral ocular edges (oe), and the brachial lobes (bl). In the mantle (m) region, there is expression in the mantle rim (mri), and the retractor muscle (rt). (B) Expression of Hox1 in the shell sac. (C) In the anterior region, Hox1 is weakly expressed in the head cover (hc). In addition, there is an expression domain anterior to the suprasophageal mass (sem). In the arms, the expression of Hox1 is clustered in the pillars of the arm pair (pf1). (D) Overview of the expression pattern of Hox1 (red) in the embryo during stage XIV. (E) Stage XVIII, Hox1-expression is present in the retractor and on the arm pillars of the posterior arm pairs IV (pf4). (F) Expression is also visible in the shell sac in the mantle. (G) Expression domains of Hox1 also comprise the brachial lobes ventrally to the optic lobes, connecting the arm pillars I and III (pf1, pf3). (H) Overview of the expression pattern of Hox1 (red) in the embryo during stage XVIII. fu funnel, ss shell sac, ol optic lobe, y yolk. Scale bars: 200 µm.
