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Figure 5 | EvoDevo

Figure 5

From: Evolution of retinoic acid receptors in chordates: insights from three lamprey species, Lampetra fluviatilis, Petromyzon marinus, and Lethenteron japonicum

Figure 5

Expression of the retinoic acid receptor (rar) gene rar3 during development of the European river lamprey, Lampetra fluviatilis, of the sea lamprey, Petromyzon marinus, and of the Japanese lamprey, Lethenteron japonicum. The expression of L. fluviatilis rar3 was characterized by in situ hybridization in embryos at stages (st) 19 (A) and (E), 23 (B) and (F), 25 (C) and (G), as well as 26 (D) and (H). Higher magnifications of the anterior regions of embryos at stages 19, 23, 25, and 26 are shown in (E), (F), (G), and (H), respectively. Cross sections of the embryo at stage 25 are through the posterior hindbrain (G’) and the anterior spinal cord (G”). The expression of P. marinus rar3 was characterized by in situ hybridization in embryos at stages 19 (I) and (M), 23 (J) and (N), 25 (K) and (O), as well as 26 (L) and (P). Higher magnifications of the anterior regions of embryos at stages 19, 23, 25, and 26 are shown in (M), (N), (O), and (P), respectively. The cross section of the embryo at stage 23 is through the anterior spinal cord (N’) and those of the embryo at stage 25 through the mouth region (O’), otic vesicle (O”), and posterior pharynx (O”’). The expression of L. japonicum rar3 was analyzed by in situ hybridization in embryos at stages 24 (Q), 25 (R) and (S), as well as 26 (U) and (W). Higher magnifications of the anterior regions of embryos at stages 25 and 26 are shown in (S) and (W), respectively. The mouth regions of embryos at stages 25 and 26 are further magnified in (T) and (X), respectively. A magnification of the tail of the stage 26 embryo is shown in (V). Cross sections of the embryo at stage 26 are through the mouth region (W’) and (W”), the posterior hindbrain (W'''), and the anterior spinal cord (W””). The exact anteroposterior levels of the sections shown in (W’), (W”), (W”’), and (W'''') are indicated by dotted lines in (W). All embryos are oriented with the anterior to the left. White arrowheads indicate hindbrain expression and black arrowheads expression in the spinal cord. Arrows in (A), (E), (G’), (G”), and (O”’) show pharyngeal expression, while arrows in (B), (F), (J), (N), (Q), (O’), (W’), and (W”) highlight mandibular expression. Scale bars for L. fluviatilis: 100 μm for (A), (B), (C), and (D); 50 μm for (E), (F), (G), (H), (G’), and (G”). Scale bars for P. marinus: 500 μm for (I), (J), (K), and (L); 100 μm for (M), (N), (O), (P), (N’), (O’), (O”), and (O'''). Scale bars for L. japonicum: 500 μm for (Q) and (V); 1,000 μm for (R) and (U); 100 μm for (S) and (W); 50 μm for (T), (X), (W’), (W”), (W”’), and (W””). Abbreviations: hb, hindbrain; llp, lower lip; n, notochord; nt, neural tube; ov, otic vesicle; ph, pharynx; sc, spinal cord; tb, tail bud; ulp, upper lip; 1 to 8, pharyngeal pouches 1 to 8.

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