Probe:	probe 1
Probe preparation:	Antisense labelled with digoxigenin RNA
Assay notes:	Hybridizations shown in this study were performed with two different probes, probe 1 (MGI:5823007) and probe 2 (MGI:5823008). Authors report that both probes gave identical results. Only those obtained with probe 1 are shown.

Structure	Level	Pattern	Image	Note
TS11: neural fold	Present		2A
TS11: neural groove	Present		2A
TS11: neural plate	Present	Regionally restricted	2A	Expression in caudal two-thirds of neural plate.
TS11: non-neural ectoderm	Present	Regionally restricted	2A

Structure	Level	Pattern	Image	Note
TS13: intermediate mesenchyme	Present	Regionally restricted	2B	Intense, precisely delimited expression in lateral somite half and adjacent intermediate mesoderm; longitudinal strip running along paraxial mesoderm.
TS13: somite	Present	Regionally restricted	2B	Intense, precisely delimited expression in lateral somite half and adjacent intermediate mesoderm; longitudinal strip running along paraxial mesoderm.
TS13: future brain	Present	Regionally restricted	2B	Expression in neural tube with rostral limit of expression corresponding with third rhombomere.
TS13: rhombomere 3	Present		2B
TS13: rhombomere 2	Weak	Regionally restricted	2B	Very weak expression in caudal part of second rhombomere.
TS13: future midbrain	Absent		2B
TS13: future prosencephalon	Absent		2B

Structure	Level	Pattern	Image	Note
TS15: 1st branchial arch maxillary component	Strong		2C
TS15: 2nd branchial arch	Present		2C
TS15: future midbrain	Present		2C	Expression in caudal three-fourths of dorsal midbrain.

Structure	Level	Pattern	Image	Note
TS17: telencephalon	Moderate		2D	Authors report intermediate levels of expression in telencephalic vesicles. No expression in the cortex.
TS17: midbrain	Present		2D
TS17: hindbrain	Present	Regionally restricted	2D	Expression in rhombic lip.
TS17: somite	Present	Regionally restricted	2D	Lateral somite-related stripe of expression running along the body wall.
TS17: limb bud	Present		2D

Structure	Level	Pattern	Image	Note
TS17: 1st branchial arch mandibular component	Present		2E
TS17: 1st branchial arch maxillary component	Present		2E
TS17: 2nd branchial arch	Strong		2E

Structure	Level	Pattern	Image	Note
TS17: somite	Present	Regionally restricted	2F	Lateral somite-related stripe of expression running along the body wall.
TS17: limb bud	Present		2F

Structure	Level	Pattern	Image	Note
TS17: 2nd branchial arch	Present		2G
TS17: somite	Present	Regionally restricted	2G	Lateral somite-related stripe of expression running along the body wall.
TS17: future spinal cord	Present	Regionally restricted	2G	Expression in a stripe of neural tissue in the dorsal spinal cord. Expression in dorsal cells of alar plate.
TS17: limb bud	Present		2G

Structure	Level	Pattern	Image	Note
TS19: 2nd branchial arch	Present		2H
TS19: somite	Present	Regionally restricted	2H	Lateral somite-related stripe of expression running along the body wall.
TS19: future spinal cord	Present	Regionally restricted	2H	Expression in a stripe of neural tissue in the dorsal spinal cord.
TS19: hindbrain alar plate	Present	Regionally restricted	2H	Expression in dorsal cells of alar plate.
TS19: limb bud	Present		2H

Structure	Level	Pattern	Image	Note
TS13: future brain	Present	Regionally restricted	2I	Expression in neural tube with rostral limit of expression corresponding with third rhombomere.
TS13: rhombomere 3	Present		2I
TS13: rhombomere 2	Weak	Scattered	2I	Very weak expression in caudal part of second rhombomere.

Structure	Level	Pattern	Image	Note
TS13: intermediate mesenchyme	Present	Regionally restricted	2J	Intense and precisely delimited expression in lateral somitic half and adjacent intermediate mesoderm.
TS13: somite	Present	Regionally restricted	2J	Intense and precisely delimited expression in lateral somitic half and adjacent intermediate mesoderm.

Structure	Level	Pattern	Image	Note
TS17: 2nd branchial arch	Strong		2K
TS17: future spinal cord	Present	Regionally restricted	2K	Expression in a stripe of neural tissue in the dorsal spinal cord.

Structure	Level	Pattern	Image	Note
TS17: somite	Present	Regionally restricted	2L	Expression in somite-related strip is in ectoderm, and potentially by a thin layer of underlying mesoderm, in region overlying lateral part of differentiating somite.
TS17: future spinal cord	Present	Regionally restricted	2L	Expression in a stripe of neural tissue in dorsal spinal cord. Expression in two areas of spinal cord with different intensity. Strong expression in most dorsal cells of alar plate. Faint levels of expression in neural cells in ventral horns.

Structure	Level	Pattern	Image	Note
TS15: 1st branchial arch maxillary component	Present		2M
TS15: future midbrain	Present		2M	Clear rostral border of expression corresponding to tectal-pretectal boundary.

Structure	Level	Pattern	Image	Note
TS22: neocortex	Present		2N
TS22: piriform cortex	Strong		2N
TS22: amygdala	Strong	Regionally restricted	2N	Strong expression in region of differentiating amygdalar mantle layer, with a complicated heterogeneous pattern.

Structure	Level	Pattern	Image	Note
TS22: cerebral cortex	Strong		2O
TS22: tectum	Strong		2O
TS22: prethalamus	Strong		2O