Probe:	Pax3 probe2
Probe preparation:	Antisense labelled with digoxigenin RNA

Structure	Level	Pattern	Image	Note
TS19: dermomyotome	Present		3D
TS19: neural tube ventricular layer	Present	Regionally restricted	3D	Expression in dorsal portion of neural tube (dorsal half of ventricular zone).

Structure	Level	Pattern	Image	Note
TS14: future spinal cord neural fold	Present		4B left	First neuroectodermal expression in neural fold before closure.

Structure	Level	Pattern	Image	Note
TS14: central nervous system	Strong	Regionally restricted	4B right	Intense expression in posterior neuroectoderm.
TS14: embryo mesenchyme	Present	Regionally restricted	4B right	Expression in 7 mesodermal patches.

Structure	Level	Pattern	Image	Note
TS18: embryo	Present	Regionally restricted		Authors report expression in 4 paired patches anterior and 2 patches posterior to the rectangular body kink.

Structure	Level	Pattern	Image	Note
TS15: embryo	Present	Regionally restricted		Authors report expression is indistinguishable from wild type embryos.

Structure	Level	Pattern	Image	Note
TS20: paraxial mesenchyme	Present	Regionally restricted	4G	Ventrally extended expression in neural tube and paraxial mesoderm posterior to hindlimb bud.
TS20: spinal cord	Present	Regionally restricted	4G	Ventrally extended expression in neural tube and paraxial mesoderm posterior to hindlimb bud.

Structure	Level	Pattern	Image	Note
TS20: paraxial mesenchyme	Present	Regionally restricted	5D	Normal mesodermal expression for 20-25 segments. Expression expands ventrally at level of hindlimb bud.
TS20: somite	Present	Regionally restricted	5D	Ventral shift first in neural tube, subsequently in somite.
TS20: spinal cord	Present	Regionally restricted	5D	Ventral shift first in neural tube, subsequently in somite.

Structure	Level	Pattern	Image	Note
TS20: paraxial mesenchyme	Present	Regionally restricted	6D	Expression in paraxial mesoderm down to caudal limit.
TS20: tail paraxial mesenchyme	Present	Regionally restricted	6D	Broadened mesodermal expression in posterior region of tail. Last 5-6 segments lose restriction to posterolateral margin of segment.

Structure	Level	Pattern	Image	Note
TS20: tail paraxial mesenchyme	Present	Regionally restricted	7D	Widened mesodermal expression withing the 41st-42nd unit.
TS20: spinal cord	Absent		7D	No expression in neural tube posterior to the 39th trunk somite.

Structure	Level	Pattern	Image	Note
TS19: dermatome	Present		9A
TS19: neural tube ventricular layer	Present	Regionally restricted	9A	Expression in neural tube in dorsal half of ventricular zone.

Structure	Level	Pattern	Image	Note
TS19: dermatome	Present		9B

Structure	Level	Pattern	Image	Note
TS19: tail	Present		9C
TS19: tail somite	Present	Regionally restricted	9C	Expression in recently formed somites.

Structure	Level	Pattern	Image	Note
TS19: tail neural tube	Present		9D
TS19: tail dermomyotome	Present	Regionally restricted	9D	Expression in dermomyotome of fourth but last somite.

Structure	Level	Pattern	Image	Note
TS19: tail neural tube	Present		9E
TS19: tail somite	Present	Regionally restricted	9E	Retreating expression in second but last somite.

Structure	Level	Pattern	Image	Note
TS19: tail neural tube	Present		9F
TS19: tail somite	Weak		9F	Weak overall expression in paraxial mesoderm in newly formed somites.

Structure	Level	Pattern	Image	Note
TS14: dermomyotome	Present	Regionally restricted	9G	Expression restricted to dermomyotome in de-epithelialising somite.

Structure	Level	Pattern	Image	Note
TS15: neural tube	Strong	Regionally restricted	9H	Strong expression in neural tube, not extending to midline.
TS15: embryo mesenchyme	Present		9H

Structure	Level	Pattern	Image	Note
TS15: tail	Present		9I

Structure	Level	Pattern	Image	Note
TS19: embryo	Present	Regionally restricted	9J	Expression domains are dorsally restricted where notochord and floor plate are visible,

Structure	Level	Pattern	Image	Note
TS19: embryo	Present	Regionally restricted	9K	Expression expands ventrally further posterior.

Structure	Level	Pattern	Image	Note
TS19: embryo	Present	Regionally restricted	9L	Ventral expansion of expression at level of hindlimbs.

Structure	Level	Pattern	Image	Note
TS19: embryo	Present		9M

Structure	Level	Pattern	Image	Note
TS19: embryo	Present	Regionally restricted	9N	Expression expanded between hindlimb bud and base of tail.

Structure	Level	Pattern	Image	Note
TS19: embryo	Present	Regionally restricted	9O	Expression fuses below the neural tube.

Structure	Level	Pattern	Image	Note
TS19: tail	Present		9P

Structure	Level	Pattern	Image	Note
TS19: tail	Present		9Q

Structure	Level	Pattern	Image	Note
TS19: tail	Present	Regionally restricted	9R	Expression widens in the tail, widening ventrally both in somite and neural tube, not reaching the midline.

Structure	Level	Pattern	Image	Note
TS19: tail	Present	Regionally restricted	9S	Broadening of expression in the tail.

Structure	Level	Pattern	Image	Note
TS19: tail	Present	Regionally restricted	9T	Expression in neural tube and paraxial mesoderm may reach the midline.

Structure	Level	Pattern	Image	Note
TS19: tail	Present	Widespread	9U	Overall expression in tail.